How did Rihanna find out Chris Brown was cheating on her?
She found another woman’s lipstick on his knuckles.
Lipstick on Knuckles: A Cheating Revelation
Explanation
Explain Bear
Listen up, buttercup. You probably think knuckles are only good for knuckle sandwiches, but jokesters like me know they are also primo spots for lipstick evidence! Rihanna, being no dummy, put two and two together. I hope this helps your pea brain.