He cums in her mouth

Seeing himself about to cum, he gets his cock partly out, just keeping the tip inside of her mouth.
"Don't swallow. Kepp it in your mouth for a minute. Then swallow it all"
Without any other warning, and with her opening her eyes wide in fear, he cums in her mouth.
He smiles and watches how she keeps her mouth open with the cum inside, dribbling by her chin, with a horrified face.
Finally she swallows
"Please, you had your ****... Let me go!"
He denies with a wicked smile
"You'll always remember this, but you'll be unable to talk about what has just happened and about we said to anyone. You'll only talk about it with me, and when we're alone and noone can hear us. Neither can you communicate it to anyone or write it anywhere" he orders her
She gets bright red trying to get a way to tell everyone what has just happened but, by now, she's unable to find it