Blowing the bottle is a completely natural sexual act performed by a girl (or a guy) on another guy, in other words, giving him a blowjob
Person A: So, how was the party last night? Did you end up hooking up with that hot guy? Did you blow his bottle?
Person B: Oh yeaaah I did blow the bottle, it was so big!!!
Person A: Will you blow mine?
Person B: No, your bottle is too small, only like half a liter. Go blow it yourself.