Is mastrubation permissible in some conditions?

I feel embarrassed asking this. But is it permissible for me to mastrubate just for the reason of semen release and colour check. Both of these reasons are health reasons but I want to clarify that no doctors are involved and I only do it once a month for the reason not to make it a habit and start to do it for desire By health reasons I mean the reason not for semen to build up and cause long term problems Please know my intentions are good and even doing it only once a month