Finding the phrase 'jazz mags' in Giles Coren's latest restaurant review (you don't wanna know), I began to worry that it might be a corruption of 'jizz'.*
But apparently not. 'Jazz' is a slang term, meaning 'to have sexual relations with'; whereas 'jizz' is just, y'know, 'jizz': East European jizz, if you're watching Shooting Aces ('shooting aces' not iself, to my knowledge, a euphemism).
Weird but true: dictionary.com has no reference for 'jizz'. Wikipedia, on the other hand (sorry...), does offer it, but only with a capital letter.
*I also began to worry that my computer records all these search terms.