The absolute best part of a man.
When a man has such Massive pecs that they could effectively be used as pillows, especally during cuddling or after sex.
As in, you just want to
lie on them and fall asleep on them so easily.
Mostly widely depicted in
art that depicts very muscular, shirtless men (Specifically Bara/Barazoku
art)
Person 1: "Oh, Babe!! Look at those big soft
pillow-pecs of yours! You'
re practically asking for me to sleep on them!~"
Person
2: "Well, my darling...that's the best part about 'em.~"