Help with Ed Begley Jnr Movie please

[Dr Milly]

Years ago I came across a movie late at night. Teen home from college all the adults are acting weird in the town and his friends mother doesn't speak but eats hair. He walks in on his parents and step sister during a party and they are all meshed together in the bedroom and Ed's head is in a bu** and he makes a joke about being a bu** head..... I don't know the name, any help please it's been bugging me for days trying to find it and a google starch and IMDB haven't helped lol?

Thanks DM.

[newb]

sounds like Society...but Ed Begley wasn't in that

http://www.imdb.com/title/tt0098354/?ref_=nv_sr_6