Sexual acts outside of marriage, masturbation, lust, those are sins. Your body simply doing a “systems check” is in no way a sin. Has your confessor every talked to you about scrupulosity? You might bring it up to him.
Maybe go over it with your priest or something, but if you’re not intending to use this as some kind of loophole, I would probably just not worry about it. But I don’t really know.
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