Go ahead about spit all over that buttplug. You'd better rub some saliva on your asshole as well. This fat plug is going to have to be stuffed all the way into your ass, so make should that it is lubed.
Now, lift your leg up and slowly started pushing that buttplug into your hole. Take your time as we don't want you to be crying in pain, at least for now. Go on, take as much time as you need. If you need more lube, use your mouth. You've already shown me that you have no problem taking objects from your ass to your mouth.
That's it my slut, work that fat plug into your ass. Feel it stretch your hole wider and wider. Once it is in, keep your leg up for a couple minutes so your ass can adjust to this giant invader.