bum cringe 

When something is so cringeworthy that is makes the cringe run down your spine to your arse.

That was so embarrassing it gave me a bum cringe.

bum cringe by pinksalamander May 11, 2009

Bumringer 

The act of inserting a vibrating cellular phone in the rectum and asking a friend or acquaintance to call said phone for sexual gratification.

I don't think I'm coming out tonight lads. I'll probably just stay in, watch Jonathan Ross and ask mum to help me with a quiet bumringer.

Bumringer by Elevant January 24, 2009