What STD's can you get from a girl giving you head?

Eh, Herpes is really the only thing I can think of, but it would be semi-difficult to NOT notice if she's having an oral-herpes outbreak.

Otherwise, you should be fine.

She might get pregnant if she swallows...Smack her in the back of the head to make sure she doesn't swallow!!!

Hehehehehe...I love that kiddy myth!

But I agree with the herpes thing up there...That's pretty much the only STD you can contract from felatio (hummers).