Why not tell her that you had a crazy dream, that you both were in the sleeper of a truck? A big dicked truck driver was pounding her while she was sucking you. Add in a few details, make it sound like it was a vivid dream. Tell her you woke up hard and can't stop thinking about it. See what she has to say. If she doesn't say much give it a little while and then mention it again during the dlldo play. Hell give her dildo a cb handle name.