When Embarrassment Strikes

This happened to someone I know. As she explains it,

Earlier today my phone rang, turns out it was my boyfriend's pants calling. While I was on the line with his pants I heard a sound of liquid falling and splashing. It was the unmistakable sound of urination. I hung up immediately; I am not supposed to hear that. But, I felt obligated to make my boyfriend aware of what I witnessed (do you witness something you hear?). So, I called him up and when he answered I asked, "Did you have a nice pee?" To which he responded "How did you know?" Then I explained what had happened.