From what I can tell, the guy with the green pants has his arms on the bottom(we can't see his head though). The guy pictured(moptop) is the top set of hands.
Obviously the girl isn't "hugging herself", because look at the left side of her body. You can see what would have to be her right elbow, but there is no way she could stretch that far. Her right hand would be tight on her stomach to hug herself that low, but the forearm is barely touching.
My take on it:2 guys, 2 girl. The guy in the green pants has his head in the girls lap. The moptop guy is leaning over the other guy's head.