Why's my underwear sometimes wet and sticky with tiny little clumps when i wake up? usually happens after i dream about being turned on.

Nocturnal emission: AKA: 'wet dream.' This is normal in adolescent and adult males.

This could be: ejaculate from nocturnal emissions. It will not harm you.

Common: It's what it called having a "wet dream". That is, while having sexual thoughts while asleep you may express semen from your penis. This is normal.

Wet dreams: Many call this natural, healthy experience a wet dream. It's the uncontrolled ejaculation of semen from the penis during sleep. It's often caused by being turned on by dreams and/or physical stimulation like rubbing against blankets, the bed or having a full bladder. It's often a 1st sexual orgasm for males. Don't worry at all. You're fine!