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!".
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.
When a male or female feels uncomfortable having sex in someone else's house or apartment. They can only fornicate in listening distance of their parent(s).
Boy: "Hey baby, wanna come back to my apartment so we can have some alone time?"
Girl: "I'm not a huge fan of sleeping with you at your place, I would feel more comfortable with you pounding me in my parents guest room."
Boy: "You definitely have security blanket sex syndrome, I should probably go look for someone else, but I think your hott so I'll be by in a little bit"