As we all know, felching primarily refers to shoving rodents up one's bum. Of course, we all have an urge to shove a small furry animal up our butt from time to time, but it's dangerous. Richard Gere, for example, was rumoured to have had a sad incident with a hamster, which required a surgeon to get it out.
Felching is used to stimulate the so called male G-spot, which is found somewhere up the anus. Putting the poor rodent in the freezer before inserting him makes him shiver, which makes him act like a vibrator, massaging your G-spot. When he unfreezes, I hope he eats through your colon.