How can I play with my ass without hurting myself

Hi! Straight male here. I hope that doesn’t matter. I discovered that I absolutely love prostate stimulation and anal play in general. I have only ever tried fingering myself. Sometimes I’m able to get through a session without damage. Most of the time, I’m sore afterwards (think fissures/hemorrhoids, not just basic soreness). Mostly, I only insert one single finger, all the way though. Only once was I able to put two in. This resulted in a fissure. I really take my time (half an hour of stroking the rim, progressive entry etc) and use sooo much lube (a standard durex tube lasts me 3-4 sessions max) I have tried different lubes, including coconut oil and vaseline. I would really like to be able to play with myself without hurting myself. Idk how. Any tips would be appreciated! Also, how long does a fissure typically take to heal, in your experience? I was thinking of waiting ~6 months or so for the fissure to heal to try again - is that long enough?