Yes I have heard of them. Never seen one yet.

I've heard of them, but I've never seen one in real life.

It seems like it would be dirty, I'd be worried about germs and STDs.

I have heard of them, haven't seen one in person though.

I find gloryholes to be exciting and disgusting all in one. There are just too many ick/risk factors for me to consider completely anonymous action, but I would consider it. I guess it's complicated.

If I ever come across a penis in a hole in a wall, I guess I'll decide then what to do!