Tip of condom slips down, but not off when having sex with girl. usually happens when she gets wet and tightens up she move around a lot. preg. risk?

Good question!: I'm glad to hear that you are using condoms and having questions about their effectiveness! Condoms can come off, and they can break. Your best bet is to ask your partner if she is willing to use another method in addition to condoms, e.g., pill or IUD. Those methods will not protect either of you from STDs, but they will give you increased birth control protection.