To be honest, I'm not sure what your friends mean by lap dancing -- why don't you ask one of them what they mean? Or ask your boyfriend exactly what he'd want from that?
In general, I've seen lap dancing refer to when strippers will straddle the clothed lap of a patron and move back and forth. No touching is allowed in most strip clubs, and the patron usually keeps his or her clothes on.
If you're engaging in rubbing against someone while one or both of you is wearing all your clothes, it's reasonably safe as long as body fluids dont' soak through both sets of clothes.
I don't know if that's what your friends mean; why don't you ask them?