It's usually said when someone is in a rough situation and what they really need is to get home. "Let us (you and me) do what needs to be done in order to make sure you get home ok."
examples:
"You're getting a little out of control, CJ, if you stay here you're just going to get into fight. Let's get you home."
"Wow, you're really sick! Let's get you home so you can rest."
"She's pretty drunk." "I can see that." "Come on CJ, you've drowned your broken heart at the bar long enough. Let's get you home now."
It can also be used in other situations that are not necessarily so "rough" though.
"You've had a fun day playing, CJ, let's get you home though so you can rest up for your big party tomorrow."
"Let's get you home so your mother doesn't worry."