Previous testing has shown
inside underpants: 35.3
under arse: 30.7C
inner ear: 35.5C

I'm guessing up my arse would be slightly higher than inner ear. I've yet to find a willing volunteer to carefully insert probe so I cannot be sure.
( wupwupwup wupwupwup, Fri 9 Nov 2007, 7:11, archived)

That implies a cooling effect from the buttocks
How odd. I think science should investigate this.
( Theoban What of it, Fri 9 Nov 2007, 7:47, archived)