How much should I charge a photographer hourly for a bikini photo shoot??

If its your first bikini shoot, id say like 35 and if it says too much, say no less than 30.

I've done like 4 bikini shoots before? Should I raise my price? He wants to shoot short shorts/hot pants too...

Negotiate. Negotiate. Negotiate.

For the shoot to happen, it basically sounds like it boils down to this:  How much he is willing to pay and how much (or little) you are willing to accept.  I would say it makes little sense for a model to price herself/himself out of the market--making some money that day modeling is better than making nothing at all.

Try to arrive at a figure that you both can happily live with and go from there.

definately negotiate. it is important to negotiate that stuff.