Perhaps, writing a story about two lovers (or more) who engage in these acts would be cathartic and even pleasurable.

Or, find a cam site and cam with someone who is good at roleplaying to enact a "fantasy" version of the type of rump in the hay you fancy.

I can't condone actually carrying it out, but, one way to circumvent the "self-harm" thing is maybe allowing your lover to drink your menstrual blood?