well most people want to make sure their partner knows whats they're doing y'kno so they're experimenting. its like in elementary and high school... they practice to be a better kisser, they practive sex in different areas. It could be that, or it could just be the soul mating i nwhich they feel eachothers presence of soul/spirit and feel the power of enrgery they have bonded with eachother and crave mroe than just a simple hug. It's a struggle between ritual and murphys law. for some, this just may happen.
It's not like you will go to hell for this, its mroe like, what you should do is wait i suppose but sex is a aprt of lfie for some lfiestyles/lifes too... God would just look at it at the gates of Heaven in the perspective of true hearts and stuff like that plus karma would balance it out if it was just for pleasure and you didnt talk to the person or were rude in soem sort of way