"I'm sorry! I'm sorry!" you say. "I tried to get them to stop. I didn't mean to..."
"I believe you" replied your wife. "I saw it with my own transformation - these tentacles have a mind of their own somehow." She licks her lips. "And lucky for you I like the taste."
You share an awkward laugh and embrace in a long comforting hug. The next thing you know she's sitting on your lap.
"Was that me again?" you ask, the concern evident in your voice.
"No, I did that intentionally. But I want to see what you'll do, or more accurately what they'll do."
You feel your tentacles shift a little and one brushes against something. Your wife shudders a little with pleasure.
"That was you" she explains.
You realize your tentacles are feeling out her longer tentacles, but also searching. One of them feels a wet area and your wife moans. You realize what's happening and try to concentrate. A moment later you feel the tentacle sliding into something tight, warm, and wet.
"Keep going" your wife pants.
You feel around slowly, gently probing. Your wife occasionally moans. Finally your tentacle find the right spot and your wife screams with pleasure. You begin sliding your tentacle slightly in and out, repeatedly touching the same spot inside her. Your wife's body begins to shudder uncontrollably as orgasms sweep over her as she screams "Yes! Yes!"
Finally her shaking stops and she collapses against you, exhausted but with a blissful look on her face. You realize your tentacles really do have some advantages. Maybe this octopus merman and mermaid thing really will be worth it.