Yep, Antony has it right. You can lung inhale. You certainly don't have to. I recommend that if you do inhale, hold it in your mouth first and then inhale, exhaling through nose and mouth, one or the other or however it pleases you.
As to speed of vaping, I like to think of my granddad puffing his pipe on a sunny sunday afternoon in his chair, in the garden.
Don't vape like you're having a sneaky cig behind the bicycle shed in between classes at school and hoping not to get busted. Got to let the wick absorb that juice to avoid dry hits and burned coils.