Denial.

Imagine a sub getting pounded by their dom with their dick/strap and they're just a whining, moaning, pleading mess. They're on the bring of release pleading to be able to cum and their dom pulls out. The sub whines and lifts their head wondering why.

"Sorry sweetheart but mommy/daddy has some things to do".

The sub's mouth drops open and they sit up "B-But.... daddyyyy/mommyyyy... that's no fairrrrr."

The sub whines as their dominant puts their shirt and pants back on.

The dom chuckles and kisses their sub on the forehead,

"Maybe next time, love, if you earn it". They walk out of the room.

The sub starts tearing up as they hear the front door open and close.

"This isn't fair. I should get to cum." the sub thinks.

With this musing, they go into the closet and grab the dildo and lube. Slowly, they get back to the bed and lube up the dildo, pressing the tip to their throbbing hole, they push it in and throw their head back. Using one hand to pump the fake dick into themself and the other to rub until they're squirting all over the toy.

Shhh, don't tell mommy/daddy though.