Our TG Caption

Seeing as she's so young you decide to prepare yet another body to merge her with and make more mature and attractive. You tie up and gag one of your bodies before using the device to switch bodies with one of hot babes you saw at the beach. Doing so will prevent her from going anywhere while in your body, meanwhile you'll just walk back as her to your apartment.
Once home you do the same with this temporary body and so you can safely return to yours. Hopefully that cousin arrives soon.