i just got a request for a birthday cake for an adult male. he wants something "adult" but there will be kids at the party too and so it cant be obvious so i was wondering if anyone had any ideas for something suggestive. like maybe something that an adult might "get" but kids wouldnt necessarily understand. i hope that makes sense. anyway, i would appreciate any and all suggestions. thanks!!!

What about a female torso in a corset or a bikini? If you're using fondant, get a food marker and make a tattoo of the birthday guy's name in a heart somewhere on it.

Debbie Brown has some nice grown up cakes that are still kid friendly. Hula girls, bikini clad girls popping out of cakes, mermaids, etc.
http://www.debbiebrownscakes.co.uk/naughty_cakes/index.htm
http://www.debbiebrownscakes.co.uk/cakes_for_men/index.htm
http://www.debbiebrownscakes.co.uk/books.htm

Check out:
www.londoncake.com
for a lot of great ideas in the adult 18+ and regular birthday section. In the birthday section they have some cakes with a guy or a girl popping out of the cake (clothed or not depending on the cake section, obviously clothed would be best for your client) ...they have a of cakes you can great ideas from....

Maybe some lips with red lipstick and there is like a white fluid on the side. I don't think kids would understand that. Anyway, just a suggestion.