I'm always looking for something to jack with and found something lately that's one of my newest favs. I take one of those small plastic chocolate milk bottles, the kind that holds like 12oz. and has a wide mouth opening. I punch a 1/4' or smaller hole in the top near the far end and fashion a small pc. of plastic over the hole. the plastic is hinged with tape. As you thrust into the bottle the flap opens and as you pull back with your cock it closes and creates a lovely suction. Then I just lube up, mount the bottle below my work bench with duct tape at cock level and go at it. If my neighbor is mowing her lawn I get plenty of stimulation. The other great thing is that it's a hands free operation. Nice if you want ass or nipple play. The important thing is to time your cum with the out stroke to get the most out of the suction.
I usually will get to the can't stop point, thrust in as far as I can and then slowly draw my cock back and let the suction pull it out of me. Have fun!