Nature a perfect artist ....
(perfect wet- gel look )
The crests of birds are of two types recumbent or recursive . The recumbent crests have feathers that are straight and lie down essentially flat on the head until the bird fans them out to where they stand out .The recursive is noticeable even when the crest is not fanned out because it features feathers ,that , when lying down curve upward at the tips ,when standing up , often slightly forward toward the front the head.
The Himalayan Bulbul I assume has recursive crests...anybody out there can shed some more light on it , do let me know .
Happy birding ...