In Jain Dharma, the rule is framed in terms of brahmacharya (celibacy / sexual restraint), not in terms of modern words like “oral sex” or “swallowing semen/fluids.”

So the question has to be answered by principle:

1. For monks / nuns (Digambar & Shvetambar)

• Any sexual activity at all is absolutely forbidden.
• This includes:

- Any deliberate arousal - Any form of sexual touching - Any kind of sexual act (oral, manual, genital, etc.)

• Whether semen or vaginal fluid is swallowed or not is irrelevant; the entire sexual act itself is abrahma (unchastity) and completely prohibited.

2. For householders (lay Jains)

The basic vow is Brahmacharya Anuvrat:

• Sex is allowed only with one’s own spouse, with restraint, and mainly as a part of household life.
• All “lustful play” and “unnatural methods” done just for strong sensual pleasure are treated as transgressions of brahmacharya in Jain ethical explanations.

In simple words:

• If the act (including oral sex, swallowing semen or vaginal fluid, etc.) is done for sexual excitement and indulgence, it falls under abrahma (unchastity) and goes against brahmacharya.
• Jainism focuses on:

- The sexual passion (rati, kashaya) it creates - The attachment and agitation of mind - The himsa that arises from intense sensuality

So, even if scriptures do not list “oral sex” or “swallowing cum” by name, they are included in the general prohibition of unchaste sexual acts driven by lust.

3. Essence in Jain terms

• For ascetics: no sexual act, in any form, at all.
• For laypeople:

- Stay within marriage - Keep sex limited, non-violent, and restrained - Avoid extra stimulation, perversions, and experiments aimed at intensifying pleasure

Such acts are understood as breaking or weakening brahmacharya, not compatible with the Jain ideal of reducing passions and karmic bondage.

You can read more about how sex and brahmacharya are viewed for Jains here