look up any word, like timebomb:
 
3.
An action occurring beneath a blanket that appears to be sexual in nature but is really mundane or innocent.
Travis and Allie were shifting conspicuously underneath the blanket but everyone knew they were prudes, so Dave deduced they were having blanket sex.
by SirHoneytoast October 15, 2007
 
1.
When a guy and a girl have sex with a blanket sheet with a hole between them in order to avoid physical body contact.
Al:"River was so shy last night that she took a pink blanket and cut a hole in it. Then we had blanket sex".
Pinky:"That's weird. She usually likes hot and steamy sex. Have you waxed your chest?".
Al:"No, why?".
Pinky:"Now I see the reason why! River does not like the Amazon forest!".
by hotbabyface January 13, 2011
 
2.
When a girl or guy takes a blanket and sticks it in between their legs and acts like their having sex with the blanket, and thrust until they get "the magic". Orgasm noises can be included if the person wishes. It's a form of masturbation.
Abby: Do you masturbate?

Jenna: Ya, but I don't finger myself, I have blanket sex.
by iluvudictionary June 12, 2010