In Jainism, sex is governed by vows and how it affects spiritual progress.

• For monks and nuns (ascetics): complete celibacy is mandatory. Sex in any form is not allowed. This is a key part of brahmacharya (the vow of chastity) for mahatmas.
• For lay Jains (householders): sex is allowed only within marriage and with self-control. Fidelity to one partner and moderation are emphasized; sexuality outside marriage, coercion, or exploitative behavior is discouraged because it harms living beings and hinders purification.

In short:

• Ascetics: absolutely no sex.
• Householders: sex only with your lawful spouse, with restraint and responsibility.

You can read more here and here .

Note: If you want, I can explain how these guidelines are applied during special periods or vows (like poshad/upvas) in Digambar and Śvetāmbara traditions.