You left out complaining about the classic of bad porn drawn everywhere: The dickbulge!
That's what's going on with the...receiver's stomach. Note that if you were to actually try inserting an object big enough to cause a definite bulge, along the lines of what we're seeing here, what you'd have would start with some really enthusiastic requests for you to stop, and if you insist on continuing there is a good chance that the flesh will tear, which will result in blood, gore, and really, really awkward explanations to attempt to give...to cops, to judges, to jurors, and to fellow prisoners assuming the guards don't just leave the person in solitary so their fellow prisoners won't murder them for being a sick fuck.
What it is not good for: Pregnancy.
What it is good for: Well, if your life goals include being murdered in prison for being one of the flavors of sicko that is pretty much shit on by everybody else...