I was wondering: is erotology and being an erotologist haram? I know that Muslim scholars such as Ibn Al-Qayyim and As-Suyooti have written about sex in the past, so is it permissible?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

It is permissible to learn this discipline and specialize in it if the learner's intention is to benefit himself and his community within the boundaries of what is lawful. However, merely learning it in order to attain sexual arousal or to accomplish unlawful purposes or what may lead to committing what is unlawful is impermissible, because the means that leads to committing the unlawful is itself unlawful.

Allah knows best.