So deep up their butt they couldn't take it out. Just like these images and your MIND.
The ass's antechamber, if you will. When it's not being Basically you just introduce gradually larger objects, kind of like gauging your ears.
When a guy blows his load, a big part of that load is fluid from the prostate to other things you can stick up your ass that will make it feel amazing. (However food and other household items will end up giving you the worst ER.