Dry humping the floor surprisingly feels so much better than masturbating. If you just go without anything it hurts. If you do it in underwear it works well.
EDIT: Sorry, had to post in a rush. Have had no experience. Knows friends that do it (._.)
EDIT2: Tried it. No, stuff does not come out. Just a boner that makes you stop. Feels good for like, 5 seconds...