Start with high-confidence sex education books, then narrow by subgenre or adjacent topics.
The Love Diet
Mabel Iam
The Good Girl's Guide to Great Sex
Sheila Wray Gregoire
The Ethical Slut, Third Edition
Janet W. Hardy, Dossie Easton
Come Together
Emily Nagoski PhD, Emily Nagoski
Sex Talks
Vanessa Marin, Xander Marin