I know one anecdote doesn’t invalid proper scientific research but … erections and even orgasm is not impossible on MDMA. I (a guy) have definitely had a bunch of sex on MDMA, not always to completion but sometimes.

The paper you linked states this at the end of the introduction, emphasis mine:

The phenomenological features of the psychological state induced by MDMA ** show some similarities** with features of the post-orgasmic state.
…
Here, we ** present the hypothesis ** that the impairment of sexual parameters after MDMA may be mediated by increased prolactin."

This is like the third time I’ve seen this post today, all in unrelated posts that just happen to be the top posts of the day.

Don’t feed the trolls, don’t fall for crypto scams