ok thanks for the imput and lol to the first post.;)
I agree with the previous poster. It can be very unpleasant, but some minority of people like this feeling, but it is quite rare sexual preference, I´ve read something about it and it was linked closely to some form of sexual masochism (e.g.orgasm denial - some men for example prefer being tied up and teased by a dominating woman who arouses them sexually for a long time without letting them ejaculate, some men who prefer this version of orgasm denial or orgasm control even ask for wearing chastity belts - something like a fetish). If your boyfriend does not have this sexual preference, please do not torture him in this way:). I would never experiment with this "game" for too long, I´m not sure whether it can also lead to some sexual dysfunctions (problems with ejaculation, erection dysfunctions etc), but I think it is quite possible if practised for a long time...
Not dangerous - but it doesn't always feel so good! For a guy, it can cause "blue balls," which is a pain in the testes/pelvis due to fluid accumulating there and not being release. And for a woman, it can just cause a little bit of achy/crampy feeling in the vagina and pelvis (some people comparatively call it "blue walls" or "blue box"). And personally, for me, I get in a realllllllly bad mood. So, no, it's not dangerous for me, but maybe for those who I encounter shortly after!