"...a Virgin? I know son. You're a creep. A naughty little 18 year-old Virgin boy. Jerking your cock to your 42 year-old Mother. Despicable."
*She slides her top down a bit and teases her nipples, before bringing her top back up*
She knew your secret. You were a virgin and she even knew your cock was on your hand looking at her. You had no choice. You were handcuffed and couldn't possibly get any more embarrassed; you had no other choice than to surrender.
*Your Mother stares at you slowly calm down to some extent.*