I have put toys up my arse hole for many years but its only in the last two years that I have started to try using bigger toys. I have several 1.5 inch thick toys, quickly moved up to 2 inch thick toys, can take those no problem.
A year ago I moved up to 2.2 inch thick which I can now take easily, then I moved up to a 3 inch thick toy which was a bit of a challenge to get through my sphincter but it went in then my arse hole clamped it in like a vice and it was a bit of a squeeze to get the bell end back out.
So recently I bought a 2.5 inch thick bell end toy which I am using and thats opening me up nicely and comfortably.
Once I am pounding deep and fast on this toy I will try the 3 inch thick toy again, but thats some bell end to get my ass hole to accept easily so I think it will be a while yet before I use it again. I am enjoying the 2.5 inch one, the bell end on it is so big and shiny and the shaft so thick its gorgeous.