"I wish you are my girlfriend". Marty's clothes suddenly disapear, leaving him naked. You start noticing Marty's skin tone start to change. His pale skin darken a little to light tan.
Marty feels sudden itch in his nipples. His brown aerola faded to pink with cup size grows from A cup to C cup. His arms still slender but with female proportion now, instead of his former big hands.
Marty's hair color lighten from dark to light blonde. He blink and his iris changes to blue. His facial feature start showing scandinavian ancestry. His lip grows fuller. His adam apple retracts and Marty make a moaning sound. No longer a male voice pretending to be female, but a sultry and female sound came out from his mouth.
You see Marty's face completely changed to your former girlfriend, Marie. Now you remember how it was started. How Marie was changed into Marty. You see Marie is enjoying the change. His hip is now fuller with a nice hourglass figure. If you are not seeing penis hanging in your boyfriend body, you will call him a she.
For the final part, Marie penis and balls are starting to retract to his body, changing into vagina. It marks the final transition from Marty to Marie.
"Finally, I'm female again", your girflriend said happily. "Now it's my turn to change you, babe." Marie reminds you that you could end up losing your identity. "I should make my wish again before she make hers", you quickly thought.
You hastily make your wish.
"WHAT THE HELL, I'M CHANGING AGAIN", your girlfriend screams while she is starting to change into ......