Step daughters/Do-good-Mom/playful/suck her tit
You, playfully: "Look at how happy Emma is, I feel so jealous right now!"
Anna freezes while her mind races to interpret what you just said while still horny. She stops pushing your and away.
You: "I am sure these are delicious!" (It is slightly less cheesy than it appears since in your love making the night before she mentioned she was extra sensitive there and you already did toy with your tongue. She absolutely loved it)
Anna, getting bright red and limp: "Come on, you know already you..." She can't even finish her sentence that you start kissing her. You start by little peck all around, avoiding her tit until finally you take it in your mouth and rub it with your tongue. Anna's whole body is reacting to you and Emma, she breathes faster and moves a bit on the chair, unable to stay still.