How traumatic anal sex is?

Varies among people: Can be traumatic because an anus is not designed for sex. It's for pooping. A vagina is created or evolved to be a two-way street (penis in and out; baby out). However, the gastrointestinal tract is designed as a one-way street, with an opening on each end. Food goes in the mouth, and the brown stuff goes out the anus. The exception is when one vomits what the body thinks is bad for the stomach.