verb To be the first one to comment on a picture/video/status on a social networking website.
Usually people want to be the first person to comment on something that they know will soon have a bunch of comments.
"Friend 1: Hey Friend 2! Did you see that picture that Jen put up of her ass in a thong?
Friend 2: Yeah, she just put it up a few minutes ago. I think I'm going to post something, breaking comment virginity on that picture!"
Luke: Nobody posted on your status that you put up an hour ago. I think ill say something and break the comment virginity.
Obi-Wan: Thanks bro