Many times it happens with me that when i wake up after sleep, I find white kind of liquid on my underwear and also some sticky liquid on the tip of my penis(if i rub it with water). My question is that is it semen ejaculation which will make ghusl e janabat wajib on me? Or is it just the premature ejaculated fluid discharged because of the erection because i didnt even feel it in the night that i ejaculated. Moreover, this stickiness and white stain on my innerwear is found in the day also when I am awake and when I haven't ejaculated but just had an erection.

If you are in doubt about it, you don't need to perform ghusl.