J Lo Lounging with A-Rod

J Lo made it official -- she and A-Rod are banging, and she let the cat out of the bag by posting a pic with him ... possibly in bed.

She pulled the ole post and delete Sunday ... briefly putting the pic on her Instagram story. A-Rod's face is covered but that's him playfully palming her head. They were spotted together in the Bahamas this weekend on a romantic getaway.

Drake who?