Can you hit the ball twice in a row?

Normally no — touching the ball twice in a row is a double contact fault. There are two exceptions:

1. Blocking: a blocker can touch the ball more than once during one blocking action, and can then play the next ball too, because the block doesn’t count as a team hit.
2. The team’s first contact: the ball may touch different parts of the body in quick succession, as long as it happens in one action (e.g. forearms then shoulder on a hard serve).