When I used to view pornography, the violence was just too ridiculous.
Also during multiple threes, fours and more persons...I just think it seemed too unhygienic. Really, condoms promote such powerful safety of passing sexual disease transmission and infrequently used. Statistically Herpes and alike is so rampant.
Say two couples a and b. Female of couple a has Herpes and doesn't tell partner. She passes it to male a. Then male a gives it to female of couple b when swapping. Then female a gives it to male b of couple b. Dirty.
The pornography films/photography have failed miserably I believe (in these areas).