"Stop! Get the banana out of your pants, please."

Oh my, I sure didn't want to say this one but I had to. I just had to. My daughter had gotten a play shopping cart full of food and some random items were on the floor. My youngest son picked up a few things and was playing ever-so-innocently with them when, all of a sudden, I see him shove the play banana down his pants and start laughing. Before I could stop myself, those words flew out of my mouth and by the time I got to the 'please' I was almost whispering. I didn't really want my other kids to hear me say that and repeat it. I mean, how would I explain that to my son's teacher??