François Arnaud Says Watching 'Heated Rivalry' With Mom Would Be 'Torture'

"Heated Rivalry" star François Arnaud says his parents are among the masses who are hooked on his HBO hit show, but he refuses to watch it with them ... and it's all because of sex.

François told "Shut Up Evan" host Evan Ross Katz it would be "torturous" to watch his show with his mother ... and he's blaming the sexually explicit love scenes.

It's kinda funny ... François says he made that mistake before and doesn't plan on making it again. Fool me once.

François recalled, "I was 16, I think, when 'Y Tu Mama Tambien' came out, and I went and saw that at the movies with my mother, sitting next to my mother, and wanted to die."