I'll give you 50 yen if you don't tell on me

  So daddy and mommy give Deryk 50 yen and Kenji 100 yen to spend at the flea market. While they're playing, Deryk does something naughty to Kenji and they both come running to us. Kenji informs us that Deryk gave him his 50 yen not to tell on him. But then Deryk says, "no no, I didn't pull his pants down. I promise!" Deryk gets in trouble, and Kenji doesn't get his 50 yen.