Riley takes you by the hand and leads you into your bedroom. "Hey honey, can you sit down for a second on the bed, oh no, nothing is wrong. I just have been thinking about stuff and I kinda wanted to tell you about a fantasy I have."
Riley has been your girlfriend for a while, but one day pulls you aside and lets you know she has a fantasy she wants to try out. She wants to be cuckqueaned, and watch you fuck other women. Preferably while she is tied up, or otherwise restrained.