pocket dial
1. verb To inadvertently make a phone call by accidentally sitting or otherwise pressing on one's cell phone (typically when it is in one's pocket). A: "Do you know why grandma called me last night?" B: "Oh, I think she just pocket dialed you."
2. noun The act of making such a phone call. I was excited when Jill called me for the first time in months, but she didn't actually want to talk to me—it was just a pocket dial.