How normal is it for the anus to bleed?

So umm it happens to me every now and then but i'm starting to be a bit freaked out cause of a medical story i heard. I asked a friend and she told me it could be a scratch from or whatever and it shouldn't be serious and said that if there is like a piece of meat or like it's not how it usually is then i should see a doc but the thing is i dunno how the "normal" thing should feel like :S... I do wash the area with water and dry it with tissues after every use of the bathroom so im not sure it's lack of hygiene. Well the amount aren't just a couple of drops, its like a size of a small coin i guess every time id run the tissue, ok it's getting uncomfortable to talk about it so i'll just stop and i hope i wasn't so ewww as this is my very first post :P