1) what exactly is this?
2) should it be straight and not bendy?
3) mine isnt straight, is this normal?
Vein-like line underside of penis?
That vein-like thing is just that... a vein. So yes they are bendy and more pronounced when erect. So ... no worries.
ah thanks, just that i read something somewhere about it being important and that it should bne straight - its put out of alignment when mastubarting up against a wall or on your bed, like thrusting with ur penis resting on ur bed