HOW TO KNOW IF A MAN HAD SEX RECENTLY - AN OVERVIEW

I am able to’t stop thinking about him. He’s incredibly shy as well, and he always gives me glances but when i look at him he looks away. My friend also said that when they mention my name/full name he quickly looks at them to find out what im talking about. He looks at me alot aswell and when my friends ttalk to him about me his voice goes up