when you are typing in online chat you enter a letter (most often the letters in the middle of the bottom line in a digital keypad) close to the space bar by mistake, and it changes the meaning of the sentence.
1. Boyfriend: Hey sweetie, I am having thisbitch on my back since last night. (letter 'b' in itch)
He tried not to do the samestupid thing more that two hundred times, but it seemed to happen anyway, and he was growing tired of breathing recirculated err.