What does this mean guys?? Lmao

Okay guys this is maybe tmi, so I’ll let you guys know now. When my boyfriend and I have sex, like in the backshot or missionary position, he would stroke for awhile..while moaning and groaning lol. While in that certain position, he would slowly let spit drip down his tongue and it’ll fall on his thingy while he’s thrusting into me🤭I know it’s his spit, because it’s a cold feeling, then it’ll start to feel warm again. Can somebody explain to me why do men spit? He says he feels my wetness once he gets past my vagina lips and I’m not dry. I just don’t get it LOL I’m too embarrassed to ask him why he does it.