I don't do it and I don't like it. I tried it once when I was 19 to make my boyfriend at the time think I was cool
I ended up getting really sick. Everyone I know who does it regularly ends up trying other things too. My boyfriend and I had a big talk about this a few weekends ago, after I saw him doing it at a party. I told him I don't want to see it, or know about it, and if he's going to do it, don't let me know. He told me he would rather not lie, so he just won't do it at all.