The Nipple Erector set|Nipple erector set, to me and my partner, seems to be a product searching for a use. While the two (different-sized) minipumps appeared well-made and had a decent level of suction, the process demonstrated in the instructions didn't work for us.

The instructions state that you should start with the smaller of the two and then slide a rubber O-ring onto your (then erect) nipple. You would then use the larger hand pump to get them a bit bigger and slide another O-ring onto that (off of the pump itself). My partner has fairly sensitive nipples, and the rings did fairly little for her (it's frankly better to use my mouth). She doesn't fit into the smaller pump, and the larger one is, frankly, "meh". This could just be something that's unique to her, though. You should probably measure your nipple sizes before you purchase (how often do you get told to do that?) to make sure the smaller one will fit.

What we did get some success with was using the larger pump on her clitoris. She seemed to like it just fine (keep in mind that you shouldn't use it for more than 30m at a stretch). In her words: "Different [than a vibrator|Vibrators], but still good."

Also, the O-rings are really, really, really easy to lose (no storage for them except on the pumps themselves), so get a small bag for those.

On me (the guy), both pumps were worthless, as I don't have particularly sensitive nipples (and no, I didn't try to get it onto my penis, there's no way it'd fit). So that's a no-go for me.

All in all, for a set of two mismatched-sized pumps, I can't really recommend the set. If they were a matched set (so that you could stimulate both nipples at once), then probably (if they fit). If you really like having rubber O-rings|The big "O" rings - Black 4 Piece Ring Set around your nipples (holding them aloft), this one's for you.