I can't help noticing that there were mainly male or TS escorts saying "no refund". I totally agree with that.
I also envy your confidence and upper body strengh.
5 years on HRT looses much of the muscle mass.
So it's all bluff.
Body language helps, mainly.
Though I once had a scary outcall.
Client wanted me to penetrate him, something I specifically would never do, and make clear prior to booking.
He was on speed or coke
kept moving me to different positions every 30 seconds, like a rag doll. He was not in control.
He was a body builder.
Got threatening when I didn't get immediately hard
{HRT means this takes a while normally, and not at all when I'm scared}
Demanded money back, which after 30 minutes was just not gonna happen.
I just kept repeating "I'm sorry but I can't give it back" over and over.
He could have overpowered me but I was in his apartment
and I calculated he wouldn't want to do anything which might bring the police
seeing a whore---embarrassment
in possession of illegal drugs (I suspected)---arrest
Eventually, he moved away from the front door.
And I could leave.
{no big deal, waiting for him to move, rather than go head to head, by trying to leave, without giving a refund}