concerns regarding a photoshoot

Hey, so i'm a model & photographer, with my own home studio, and I regularly collaborate with other models & photographers

I did a photoshoot the other day with a guy (I was the model) in my home studio, this was a fashion based shoot, however once the shoot began hes became very pushy, and tried to get me in underwear, and even nude, I managed to stand my ground, but I am mortified by this conduct, and wondered what action I can take, as surely this is not appropriate or professional behaviour

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