Henry would have the advantage over you if you went to the park as a kid, but with only two of each condom type in the box, if you change now, there's no going back to being Scott. Not that you want to be a scrawny fourteen year-old, but it's a good way to lay low and figure this out.
Or would he have the advantage? It's not night anymore, and the park is a public place. You smile as a plan comes into your mind, you might even be able to get more than a hint out of Henry. You head downstairs and pop you head into the living room where your parents are watching the news. "Homework's done, I'm going to the park."
"Okay, just make sure to send a check in text once in a while." You father calls back.
"Sure!" God.. it sucks being a kid again, protected sure, but less freedom. You head outside and hop on your bike, already missing the ability to drive. You get to the park and cycle around until you find Henry sitting on a bench, you stop in front of him and just glare.
"What do you wa... Bro?" When you nod he looks disappointed. "Damn, I was hoping for another round with that brawny dilf from last night."
"You promised me a hint, you didn't say anything about a booty call." You say as you lean on your bike enough to keep one foot on the ground. "But if you really want him, he has a twin who's now my dad. But he's also married, still, he did fuck his brother, so maybe he would pound a little snot-nosed shit like you." You puff out your scrawny chest, trying to look intimidating. "Hint. Now."
"Hey, watch it. Keep insulting me and I might change my mind. I'm also bigger than you, now." Henry is obviously in the mood to be pushy but now you pull out your secret weapon.
"Yeah, but your an adult and I'm a kid. I start screaming that you touched me and you'll have enough problems. So...?" You smile sweetly.
"Fuck, bro. That's cold. I was hoping this experience would make us closer." He leans back on the bench and looks you up and down. "I guess you noticed I removed the instructions before sending you the box."
"Ahh.. well, no, I just thought there were none.." You blush a little that that thought hadn't crossed your mind.
"Okay, so I'll let you in on three things." A finger goes up. "There are two of each condom, so there are actually two that will turn you back to the old you. But each condom is one use only." Henry lifted another finger. "Both of a pair will turn you into the same person, but someone else will wind up someone different, so you can't test them on other people, gotta try them yourself. Like if you tried that dilf one again, you'd be the same guy, if I put it on, I wouldn't become him but someone else. I dunno why, it doesn't explain it." Henry lifted a third finger. "If you actually use it for sex, you both change. Each into the respective person that condom would make them. Only the person wearing the condom will remember though."
You carefully pay attention, trying to remember everything. "Fine.. that still doesn't tell me which is the right one."
"Hey, I gave you three hints instead of one. That's what you get." Henry stands up. "I'll even throw in a fourth. If you reaaaalllly want to go back to being one of the people you became, you can order refills, the number is on the back of the box. But call me if you turn into another muscle bear. I'll give you more hints for some fun." Henry holds his fingers against his head like a phone before heading off back towards his car.
With nothing else to do, you turn and start biking back home. A couple of blocks from the park though you hear a car honk. You turn and see Mark in the driver seat of a car. "Need a lift, squirt?"
You nod and get off your bike. It only takes a moment to hook it to the bike rack on the back of the car before you slide in the passenger's seat. You wrinkle your nose a little. Mark had just come from the gym and he smelled like it. Like most teenagers he just seemed to reek b.o. some days. Scott's memories were getting stronger it seemed. Would they over ride yours if you stayed like this too long?
The ride back to the house is quiet, Mark isn't the chatty type, but you know he looks out for Scott. The exact opposite of how you were with Henry. The thought actually makes you feel a little guilty about the whole thing. Maybe you did deserve this torment for a while.
Once back at the house you unload your bike and walk it into the garage. Mark ruffles your hair as he walks past you into the house, with you following a moment later. Not in the mood to socialize with your, well, you guess they are your family, you head back to your room. You pull out the box and look it over. Sure enough there is a number to reorder on the back, just like Henry said, so maybe the rest was true, too.
You start to dig through. When you find the one that turned you into Jay you pull it out, grab a sharpie from your desk and write Jay on it. Hopefully that will last through reality lurching around.
So, size does seem to matter. You start digging through, you need something bigger than you are now, but not as big as Jay, your old cock was definitely not that big. Finally you come up with five in the inbetween range. It's hard to tell exactly how big they are without something to put them on, and you don't want to risk doing something weird to a banana.