If you don’t mind my asking, what brand are the boy short things? I struggle with finding comfortable underwear for breeches and am always looking for ideas!
ETA: I’ve ridden in silicone full seats only for a while now (mostly European brands like Ego 7), and one thing I can affirm is that with washing and wear the grippiness reduces significantly, to the point where they can actually become too slippery! I wash mine inside out for this reason to prevent abrasion of the silicone against other things in the machine. But it still happens with time. You can tell if you look at used ones in a consignment shop.