When a male attempts to stuff a lot of napkins up his asshole for sexual pleasure. A form of masturbation. Old men tend to use this method more than younger men. Occasionally this method is overused and the asshole tends to stretch and rip, causing a bleeding asshole.
My grandpa tried the napkin testosterone boost last night. Now he went to the doctor and had to get surgery on his ass.
OHHH! yeah! my napkins helped my body fill up with pleasure last night!