This toy could be used for both vaginal and anal insertion. It has a wide, flared base which makes that nice and safe. That same base makes this one a great choice for use in a harness. I haven't used it in one yet but in the follow-up review, I will explore that more since I will have one soon.

Do keep in mind, this toy doesn't vibrate so if that's what you want, you should look elsewhere. Also, if you're looking for something that will give you a lot of g-spot stimulation from an extreme curve or the sensation of a large head though, you aren't going to find it here. I was able to get some g-spot stimulation but nowhere near as much as something with a more hooked shape would give me. The toy also doesn't have a large head for those who really enjoy that.

I noted one review said this toy could be used to pack. I personally would not try that because the toy really won't bend enough to fit in someone's pants comfortably. I would definitely recommend it to other trans men for use strictly in the bedroom though, since the proportions of this toy would look very natural and average with all sorts of body shapes and sizes. The only thing that would look off would be the color. None of the colors available are that close to actual skin tones except perhaps the caramel. That's not a big issue for me though.

Did I also mention this toy is really fun to practice oral on? It totally is.

The O2 Mark is made of 100% silicone, which gets a 10 on Eden's safety scale. It's very safe and can be sterilized. This toy has no smell or taste at all.

I always dreamed about finding a realistic, insertable toy that felt like the real deal and this is the closest I've felt so far. The material really is as lovely as everyone is saying it is. The veins on the shaft press down under one's fingers in a way that is unnervingly realistic and when you squeeze it firmly it really does feel like a hard, happy erection. The silicone has quite a bit of drag to it which I found annoying, but if you put a little water-based lube in your hand or take it in the shower it pretty much disappears when wet. I would've just really loved it to feel that smooth even when dry to complete that realistic feeling.
The head of this toy is shiny, while the shaft is matte. I think it would have looked better if the whole thing was shiny or matte, not both, but that's just my opinion. The head is also the squishiest part, and can be pushed down into itself to about half its original size.

The silicone is dual density, meaning the outside is squishy and the inner core is very firm. I think this toy could've used more of the softer silicone on the outside honestly. It has more on the bottom side than on the top side, and it definitely feels more real and comfortable on that side. The top side feels really hard, especially right before the completely squishy head. Insertion would have been easier with just a little more give right there, and it would just be even more fun to touch. I can't push the soft layer in much on the top side, but I can give it a nice squeeze if I apply pressure to the bottom side because of the squishy ridge. The sides are in between the top and bottom in thickness.

The toy is somewhat flexible. If you hold it in your hand and wiggle it, it flops around a little bit. I think it would be particularly good for harness use because of this. It will stay in place and not bend everywhere when trying to play. It won't bend a lot even if you apply a lot of pressure. I could almost bend it into an "L" shape, but that's about as far as it would bend. There's no way it would go in half like a lot of super soft toys I've seen.



Another really nice thing about this toy is the way it retains temperature. It gets nice and warm if you put it in warm water or against your skin for a while. This also really helps with the realism aspect.

All compliments aside, I really hate how much lint and hair sticks to this material. I brought Mark to bed with me to have a, um, very good night and it was covered in stuff before I could even get it near me. It's hard to get it clean when there's a lot stuck to it, it won't just rinse off easily. I have to run it under water at every angle for a significantly long time.

The shape is just as realistic as the material. It looks like a stylized penis, with pronounced veins all along the sides and one small one on the top side near the base. The bottom side has no veins but has a large ridge of the softer silicone instead. I really couldn't feel the veins at all during use but they were nice to touch and look at. The top is quite detailed right down to a urethral slit and frenulum. There's also a Tantus logo at the base of the shaft.

The head is defined somewhat but isn't particularly larger in girth than the shaft. It's slightly bigger just around the edge but not enough for me to notice any "popping" sensation during insertion.

The toy has a slight curve to it, which should be good for g-spot stimulation, but the squishy head makes it a little harder to apply any pressure there. The curve doesn't really hold up that much during use, either, depending on what angle you hold it at. If you hold it forward with the top of the head facing up, it basically goes straight.

As for the size, I think this toy would be best suited to people who aren't total beginners but aren't size queens either. It's about 6 and 1/2 inches long and 1 and 3/8 inches in diameter (4 and 3/4 in circumference). The product size feature here made this toy look a little smaller than it turned out being. It's not huge at all though. It's still about the size of a nice, average penis which is exactly what I wanted. Though I don't have any other toys this exact size, I do have ones slightly smaller and this one definitely feels its size despite the squishy material. There really isn't enough soft outside layer versus firm core to make it seem smaller when inserted.

I wouldn't consider this toy discreet at all since it looks pretty realistic. Because of the average size though, it could probably be hidden well in a suitcase.

If you like to use toys for thrusting, this one's great provided you use some water-based lube to alleviate the large amount of drag. It doesn't eat lube too much. I only needed to apply a generous amount the first time. It feels very realistic internally that way and that's a lot of fun. Unfortunately, Mark was just a little bit too big for me to enjoy as comfortably as I would like. I'm generally used to toys with a diameter of about 1 and 1/4. I'm hoping with more use this will change because I really love this toy. Don't let that detract from your decision to get it though if it sounds good to you because I am just abnormally small, I swear. This toy really is lovely and perfect for people who enjoy penetration from penises in general.
I was able to get a little g-spot stimulation from this toy but nowhere near as much as I would from a toy with a more extreme curve.

Rotating it internally feels interesting but the curve gets more noticeable that way and it isn't that pleasurable an experience for me. Your mileage may vary. I just didn't like the feeling of the curve suddenly bending back into place in an odd angle.

The wide base keeps it steady on a flat service and in the bath tub it even acted mildly like a suction cup, making it nice and sturdy for riding it.

It would have been nice to have an actual suction cup on the bottom, and it would have been interesting if it vibrated, but I didn't particularly need either. It was fun to use a bullet vibrator externally while playing with this, for twice the stimulation.

You have plenty of options for cleaning silicone, and this toy in particular since it's 100% waterproof. You can wipe it down with a toy cleaning wipe, clean it with antibacterial soap and water, or sterilize it by boiling for 3 minutes. You'll definitely need to rinse it off a lot to get rid of the lint and stuff it will undoubtedly collect like mine.

Silicone toys are compatible with water-based lube. Silicone-based lube will harm the material and Mark is too nice to accidentally ruin, so don't use it!

This toy is not difficult to store, but you'll want to stick it somewhere that it won't pick up the aforementioned lint and stuff. I've been keeping mine in its original box, but a good option would be inside a toy box like the Devine ones sold here, or a satin bag.

Mark was packaged in a basic clamshell package within a clear, plastic box. It wasn't discreet at all since you could see the toy right there. The graphic design of the packaging was appealing and bright. I wish the box was less flimsy so I could use it for storage in the long term. It's basically designed to be thrown away immediately after opening.



The box says "100% silicone" in the front, has a small Tantus logo, and says "The world's best soft toys for adults" as the bottom. The wording isn't exactly discreet either, not that it would make a huge difference when you can see the toy right through the box. On the sides and back are a few paragraphs (In multiple languages on one side.) about Tantus toys and their quality.