Bring 2 condoms, but prep them with small holes in the tips, and some silicone lube. Suck him first, and then use some lube to jerk him off. and rub his lubed cock up and down your crack, pausing at your hole frequently. That my put him over the edge to begin with. If not, get sneaky. Put the condom on for him, stretching it tightly over the head. It may break immediately, but if not the silicone lube will help break it once it is inside you. If he stops to replace the condom, your second one is treated the same way and should break as well. After that, either he stops fucking you (not a chance at that point) or he goes bare inside you.