I guess he wants help resisting the charms of a voluptuous, bi-curious teenaged girl? I can't help him there; I can't even resist the charms of my voluptuous, bi-curious wife.
Easy...when she does..picture yourself on the receiving end of a big hairy male in the showers of the county jail..because that's where you will be.
On a serious note, avoid being alone with her in a room. Make sure someone is with you as a witness. You won't be able to talk to her because most sixteen year olds I know don't take rejection well.