Because as he emptying himself all over her pussy they found themselves in each other's bodies.
Samantha: Oh my god I think we have swapped bodies Michael?
Samantha: Michael your cock feels so hard at fulfilling!
Samantha: Does it always feels this powerful when you come Michael?
Michael: Isn't it intoxicating shooting cum Samantha!
Michae: I never knew my cock!
Michae: my cum all over your pussy feels wonderful Samantha!
Michae: does your pussy always feel this good after sex Samantha?
Samantha: O yes and you will be feeling that hours to come Michae!