[Mocha Man]

Alright, let me preface this by saying that I am a newbie to mechanical stuff. I've been riding for a while but recently moved out from living with my parents. My dad is an amazing mechanic but I live nowhere near him now and can't exactly ask him for advice. I tried learning everything from him that I could while living with him, but it was really overwhelming at times. So talk to me about parts like you'd talk to a two year old trying to learn words for the first time. I won't take offense.

Today, I was doing an oil change on my bike. Everything was going smoothly and I went to refill the oil. I got all that was needed in there, making sure to let the bike idle temporarily before topping it off. Once that was done, I turned the bike on again and let it idle for a little while longer to make sure there weren't any leaks. While it was idling, this O-ring (about 1 3/8 in. in diameter) fell out from underneath my bike. I shut the bike off and tried matching it with where it came from, but I can't find anywhere underneath it that this would go. I know this is probably a really dumb question and I feel like an idiot just for asking, but could someone help me identify where it goes? I thought I was doing a good job of keeping everything in tack when I took the oil filter out but now I'm second guessing that.

Thank in advance,
Nolan