I have extremely powerful anal orgasms and can tell when others have them or they're fake. My teeth go numb, I kick, and I'm not the biggest bodybuilder but at 220lbs and 14% body fat, it takes a lot to keep me from bucking a guy off of me, Im pretty strong. Best thing about them is I can have them over and over and over there is zero refractory period.
If anyone wants to see what real ones look like, watch Jason Vario's videos with his last and his more recent guy. Nathan Brooks is I guess his current boyfriend and he has them with Jason, and I think his husband or ex husband called that_switch has them and they are great to watch.
If you want to train yourself to have them I recommend the Aneros line of toys.