The act of inadvertently calling someone on a cellular phone, when your phone is in your pocket, or purse, or some other seemingly inconspicuous place where it should not be making calls.
Your Crazy Ex: Hey, I saw that you called. What's up? Wanna hang out? Wanna get back together? I MISS YOU SO MUCH!!!
You: Eh, sorry for the confusion, but I didn't mean to call. I must have butt dialed you.