what's the movie where a white boy is in bed with a back boy and they get walked in on by his mom

The movie you are referring to is "Get Out" directed by Jordan Peele. However, the characters you described are not in a romantic relationship but rather friends, and it is the father, not the mother, who walks in on them.

thats not it

Apologies for the confusion. I misunderstood your description earlier. Could you please provide me with more details about the movie you are referring to?

then they pretend there working out and the white boy puts his sweat shirt back on

Thank you for providing additional details. The movie you are referring to is "Meet the Fockers" (2004), which is a comedy film directed by Jay Roach. In one scene, the character Greg Focker (played by Ben Stiller) is in bed with the African American character named Jack Byrnes (played by Robert De Niro) when Greg's parents walk into the room. To hide the fact they were in bed together, Greg pretends they were just working out and quickly puts on a shirt.

nope

Apologies for the confusion again. Without more specific information, it is challenging to accurately identify the movie you are referring to. If you can provide additional details or clarify any other aspects, it would be helpful in identifying the correct movie.

both of the boys were 16-15

I apologize for the multiple misunderstandings. Unfortunately, I still don't have enough information to accurately identify the specific movie you are referring to. If you have any other details or plot points that could help narrow down the options, please provide them.

the white boys sweat shirt was a green color