its another way of saying: lets get it started lets get on it lets roll lets begin there are a lot of variations to this...

"Let's hit it!" = begin

I agree with the above post. In my opinion, the phrase, "Let's hit it!", by itself seems a bit awkward but things like; "Let's hit the road!" (My Dad uses this often when we travel a long distance in cars. "Come on kids, it's time to hit the road") "Let's hit the town tonight!" "Let's hit up this ___(place)" (meaning, "go to, check out") These all feel more natural. On a side note: "Hit (pronoun) up" can also be a very informal way to say "make contact with (via phone, email, message, etc)". I use it often though the same couldn't be said of my father... For example, A possible conversation with a friend. Me: "Hey buddy, hit me up when you got a second." Friend: "Alright, sounds good. I'll hit you up after I get off of work."

Gangbang time!!