That guy who wants to sit around scratching his ass all day instead of doing anything to help himself or others, and still expects the world to supply his every need or desire. He has no legitimate disabilities but would rather live in his parents' basement instead of even trying to look for a job.
I think the term ass scratcher was coined on The Family Guy, but I'm too much of an ass scratcher to confirm that.
When one man (or lady with strap-on) has three or more naked women stacked up and willing to take it doggystyle in successive turns by the one man (or lady with strap-on). The result of their positioning, lying on top of one-another, forms a stack of asses known as an ass-stack.
"I had 5 girls, naked and willing, in an ass-stack" he said.
Action in which one person bites the buttocks of another person for as long as they can. This is typically a party game in which someone yells "ass rodeo!" and goes after someone.