Musannaf Ibn Abi Shaybah

Hazrat Aamir says that if a man, while fasting, engages in foreplay with his wife and pre-seminal fluid (madhi) or prostatic fluid (wadi) is discharged, then making up the fast (qada) will not become obligatory upon him until that thing is discharged which makes ghusl (ritual bath) obligatory, i.e., semen (mani).