system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do I sometimes feel my pulse in random parts of my body?

Last night while laying on my belly trying to get some sleep I noticed that  I could feel my pulse in my butt. Sometimes I can feel it in a leg, an arm, or even my hand as well. What's going on?
gpt
Blood goes through these areas (duh). This expands the blood vessels a bit every time because there's pressure coming from the inside. 

This is normal, and your body "knows" this (the biologist inside me is cringing right now). You feel it all the time, but your brain ignores it. 

However, sometimes you just don't have a whole lot to keep your mind occupied. That means there's nothing to "down out" the sensation of blood flowing through your body, because there's nothing that is directly more important for your brain to occupy itself with. So you become consciously aware of it. 

It can also be that because of the way your body is positioned, a bit more pressure is on that particular artery you're feeling.