As you watched intently, focused on Ryan's performance. You thought that he shouldn't be the only one getting in on some of the action. You briefly shift your attention over to his girlfriend who is just watching Ryan with a mix of shock and disgust.
"That's so nasty! Control yourself..." She said.
"Nngh... I'm trying," he said, his knees buckling from the pleasure.
'Maybe she should see how hard it is herself' you think to yourself. You reach down to your phone and start typing in the still open app.
'Ryan and his girlfriend switch bodies and lives.'
As you hit enter, you immediately see a change in both of their demeanors. Ryan in his girlfriend's body looks relieved that somehow he was no longer forced to jerk himself off, but that relief didn't last long. His attention was brought to the loud moaning in front of him.
"Oh god... What's- what's happening? What... unnhh... is this weird -fuck- sensation?" She said between pants and grunts.
As she looked down, she was greeted not with her usual body, but a naked, masturbating male body. She didn't want to see the truth, but as she gained a small sense of clarity, she looked up and saw her own body, who looked like they discovered the same thing.
"Rachel?" Ryan asked.
"Yeah, Ryan. Ohh God, it's me."
"How is any of this even happening?" He then began to notice her struggling with all the new sensation. "Oh babe, I'm sorry you got stuck like that."
He walked over to her and put a hand on her now much larger shoulder. At this point, a few people gathered and stared at the odd sight, but with a quick change, you made anyone watching uninterested in what was going on.
"Ryan, I'm not sure... But... Oh fuck. I think I'm getting close," Rachel said.
No sooner had she said that, you watched as long streams of cum flew out onto the sidewalk. She bucked and yelled as she had her first male orgasm, with Ryan standing by getting an outsider's perspective.
When she finished, you typed in a change so that she would no longer be compelled to masturbate.
"Thank God, it's over... But what now? Are we stuck like this?"
"I hope not. I can't live like this," Ryan said, reaching down and grabbing his breasts.
"Well neither can I! Your body is so big and bulky," Rachel said as she mimicked Ryan and grabbed her large pecs. As she squeezed, she felt the hair on her chest. "Ugh, and all this hair everywhere. So gross!"
You saw as she looked under her armpit at the bushes underneath her arm before looking down at the other bush on her crotch. "If we're stuck like this, I am so shaving this."
"You're not the only one with problem, I lost my dick, Rach!"
"And you think having this is so good?" She said gesturing to her crotch. "I'd rather have my lady parts back."
"Well, we better find a way to change back. And in the meantime, we need to find you some clothes soon. I can't have you in my body getting arrested."
Rachel suddenly realized that not only was she in the naked body of her boyfriend, but more so, she was naked in public. Instinctively, she covered her crotch with one hand and put the other arm across her chest.
"Here, for now, try to cover up," Ryan said as he pulled Rachel's shirt off, exposing his new bra-enclosed breasts to the world.
You decided to spice things up a little, so you made sure that they maintained the original sexualities of the bodies they're inhabiting. As Ryan hands over the shirt, Rachel doesn't take her eyes off her former breasts as she places the shirt in front of her dick. Which you can see is starting to tent slightly. It seems like Ryan's gaze is lingering over his former well scullted and slightly hairy chest. He shook the feeling and grabs Rachel's muscular arm and led her down the sidewalk.
Realistically, you could use the app on them more, but maybe it'd be more interesting to move onto someone else for the moment.