I get hard with women who come with me with free willing but I can't get hard with women that seems forced (by money) to have sex with me. Psycologically speacking why does this happen? I get extremly hard when an women shows interst in me but I can't get hard with bootiful hookers if I see that there's no free willing for her to have sex with me.
What does it happen scientifically and psycologically speacking?