If you're super tight, it's probably not going to happen right off the bat, unless you have phenomenal muscle control. (I find that's usually only guys that bottom often and thus, aren't too tight.) Be horny. Very, very horny. Nothing will make it fit faster than being so horny you can't see straight. You can make your hole take it if you want it badly enough. Lube. use lots of it. Coat their cocks in it and make sure you slide a bit up inside you too. If you're a poppers guy, take a bit hit or two. Logistically, if there is one with a bigger dick or curves up, lay him down and straddle him. Get him inside you and ride a bit before letting the other guy enter you from behind, above the first guy's dick. Once you get them both inside you, your first reaction will be that it's too big. It's not. Let them stay there and relax your hole before bearing down on them and telling them to fuck you hard! Once they get the rhythm, you'll be in heaven and you'll wonder why you never did it before.