hi, Im very very tight and only had anal once. It felt amazing. I know all that about lube, taking it slow and relaxing. However, after I had a poo ( most likely one day after I had anal) there was some blood. ( maybe because I am very tight and that was just inevitable) Have you ever experienced that?
That can happen occasionally when you're first getting started, or when you've gone too fast too quickly before being warmed up and relaxed enough. Make sure you take a break for it to heal before trying again, and next time warm yourself up with some fingers or a butt plug for a while before you have sex. A little bit of blood isn't a big deal, though should be avoided if possible, and with more experience is far less likely to happen.