It kind of goes without saying, this is not something to just ignore, A rectal bleed can be caused by overexertion in the case of extreme diarreah or constipation. It can also be caused by overly vigorous wiping or low-quality toilet tissue. If you're losing more than a tablespoon or two of blood, something is VERY wrong in your lower GI tract - best case it's a simple case of haemorrhoids. Worst case you've got a performation somewhere in the colon, rectum, and/or distal part of the large intestine. To differentiate the two, you're gonna want to inspect your butthole somehow to, uhm. assess the damage. A very gentle pass using TP, applied with a blotting motion, can be useful to localize the bleeding if it's haemorrhoids - they are usually external, and are not super concerning, they should heal if kept clean. However if your exterior rear end is free of injury, by process of elimination, the blood is coming from inside your ass. It could be at your sphincter, or worse, deeper in the bowel. That, to me, sounds like an urgent care/ER trip.
I am at a loss for what you can do to treat it yourself. For an internal bleed, aside from staying in a reclined, comfortable seat, being very gentle when wiping (maybe use wet wipes or a bidet), and watchful waiting, there's not much you can do.
External bleeds can be treated by gently cleaning the damaged area wirh soap and warm water. Preparation H (which contains phenylephrine, of all things!) will act as a vasoconstrictor and topical analgesic, reducing blood flow and irritation. Loose fitting underwear also is helpful. If circumstances warrant you could even go commando and let it all hang free.
Rectal bleeding with symptoms of weakness, dizziness, or fainting is associated with at least 1 liter (2 pints) of blood lost is a medical emergency. Seek medical care immediately. Sudden loss of 2 liters (4.2 pints) or more of blood can be dangerous, if not fatal.
I dont think I need to say this, but, just in case, refrain from cramming horse dildos into your butthole if you're experiencing bleeding or discomfort. It's also not very good to have liquid feces near open, bleeding, cuts. I hope I don't need to explain why.