Cakrasaṃvara Tantra
en.wikipedia.org
Cakrasaṃvara Tantra
Karmamudrā practices may have been at one time a part of the path for all tāntrikas, and it is clear that in Indian Buddhist tantra such practices were commonplace.
However, this is also a dangerous path, for if passion seeks to serve the ego, the explosive result creates havoc. Hence, the dynamic of sexuality in Anuttara-yoga tantra is always pyrotechnic and potent. The ordinary chemistry between men and women is a powerful expression of the fundamental dynamic of phenomena.