This is in a case where a guy really likes a certain girl.
He talks with her, thinks about her and then holds her hand. That gives him a feeling of excitement that she is willing to hold his hand.
If he is with a girl that he doesn’t care about, that won’t excite him. Even having sex with her won’t leave him excited about her. He will feel like, all right I had sex. But the emphasis will be on him: I had sex, she is kind of secondary in his thinking.
But back to the girl he likes. He gets excited that ‘she’ holds his hand. After a while, that isn’t as exciting, but putting his arm around her is. This continues when they first kiss. Guys have a whole rating system using something they are familiar with, baseball, to describe something they are learning, girls and their bodies. One guy asks the other “How far did you get?” the other guys says first base. Or I got caught trying to go for second base.
An interesting part of this is that when a guy really likes a girl he stops talking with his friends about how far he got. And he doesn’t want his friends to get a chance to get up to bat.