Does masturbation and watching romantic scenes that emit a mucous fluid necessitate ghusl (ritual bath) or is wudu (ablution) sufficient?

Ghusl is obligatory if semen is discharged. Semen is recognized by certain characteristics, including: pleasure upon its exit, or its gushing forth, or if its smell is like the pollen of a date palm or like the smell of egg white when dry. If these characteristics are absent, then it is not semen and does not necessitate ghusl.