They say that the average human being swallows two litres of other people's saliva during their lifetime. I didn't have my first kiss until I was 21, because I'm clinically shy. After the kiss I told the girl it was my first, expecting her to laugh, but she didn't. She told me to open my mouth, so I did, expecting another kiss, but, instead, she said "Here!" and spat down my throat. In some ways it ruined the moment.