In Death Note, how far could sexual interaction go with a shinigami before it broke rule XXXVI?

As the internet knows, in "How To Use" XXXVI, the following rule is stated:
"There are male and female gods of death, but it is neither permitted, nor possible for them to have sexual relations with humans. The gods of death also cannot have sex with each other. "

Now, this rule isn't to prevent romantic interaction, as a shinigami can be in love and act like it, he will only die when he steps in to save his love interest. In other words, love isn't forbidden, purposefully saving lives is. No, the obvious would be that this rule addresses breeding. Nobody wants half-shinigami running around in either worlds. Or at least, the shinigami king doesn't.

But if something is not possible for a shinigami, why is it also forbidden? It's a pretty awkward catch: in humans (and supposedly also in creatures as sophisticated as shinigami, who have a culture and a personality) sexuality goes way beyond reproduction. We guys in the human world have hundreds of ways to spend a steamy hot night without actually doing the deed. So what is "sexual relation" supposed to mean?
Here are the two options that seem obvious to me, but neither feel entirely satisfying.

1) If "sexual relations" are both forbidden AND impossible, can a shinigami behave as lewd as he wants, with humans or peers, since none of it can be called "sexual relationships" (they're impossible) therefore everything sexual he does is by default allowed? (In which case, the interdiction would only exist in case it somehow became possible for shinigami to get laid, I guess?)

2) Or, is the rule twisted/badly worded, and implies that intercourse is not possible but also that all and any sexual behaviour is forbidden, despite being completely feasible? If that was the case, it begs the question why this rule exists in the first place, since it won't cause any offspring. That would also be the first time a Death Note rule is so imprecise and ambiguous.

The whole question could be dismissed by saying that shinigami just won't be interested in it in the first place, but I ruled it out, given how diverse their personalities are and how much some of them like to mess with humans in every way possible out of sheer boredom *am I right*.

Both solutions seem problematic. Is there any info out there that I missed, or any thinking I got wrong? Thank you a lot for helping me solve this mystery.
Asked Sep 07, 2017

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