Sometimes when people are explaining things to me or when they are teaching me I get a slight tingling sensation in my entire head. I'd definitely compare it to a mild buzz from a drug of some kind. It feels so good yet so mild and unobtrusive that if you could easily and regularly reproduce it from taking a drug without any negative side effects it would surely be a very popular drug.
The first time I noticed it I was in kindergarten. It was a Montesorri preschool in Durham, NC where I was born. A female classmate of mine was demonstrating how to assemble or use some sort of toy. I believe it was puzzle like. She was speaking about it while she did it and explaining very well the steps you take, in what order and how to complete each step. I remember getting the tingling feeling and noticing it and suddenly becoming less interested in what she was showing me in the foreground and more interested in the buzz that started in the back of my head and slowly consumed my entire head.
Today I most often notice the buzz at work. I work in tech support and often have to listen to customers explain their computer network/servers/internet services and environment in detail. Sometimes when they explain it the right way I will get the buzz. I love it but it never lasts more than a minute or so. The fact that it never lasts more than a minute I think makes it more enjoyable too. Knowing that I only will get to enjoy it for a minute or so makes me concentrate on it more and makes it more special.
Sometimes I try to explain it to friends but no one I've ever explained it to has ever been familiar with anything like it. I think it's really odd that it is a specific feeling that I only get during really specific interactions with other people. I wonder if I've learned to expect it or create the feeling around those specific interactions because I first felt it under that type of interaction. Who knows?