Looking at the balloon happily you think about how much your girlfriend will love it, it's just her style. Although you do feel a little silly a 19 year old man carrying around something that more likely a little girl would have.
As you approach her, you can't beleive that such a beautiful girl would ever agree to go out with you. You also can't beleive she has a balloon almost exactly the same as the one you got for her, except that one is blue.
You are madly in love with her and kiss and fondle her hot little body and then start messing about, you decide to inhale the hellium from your balloon so you can speak to her in a funny squeaky voice. You do it fills you lungs almost immediatley and seems to spread through the rest of your body.
"Woah, that felt really funny" you squeak out in a high pitched voice.
"Hehe, you sound like a little girl" she says giggling "Let me join in" she says inhaling the gas from hers. She coughs as it fills her lungs, but it sounded quite deep "He....he hey.........what's up with mine, my voice sounds really deep like your normal voice, I thought it was meant to make it all squeaky like yours did. OH NO.....what the" she says looking at you in shock.
Your voice still squeaky you reply "What why are you looking at me like that...............wait a minute, why am I looking you straight in the eye, I'm a foot taller than you". but that's not the only thing to happen as you feel your body shift taking on feminine proportions and hair tickling your shoulders.
"Oh no your still changing........and I, I'm starting to feel a little funny too" she says panic in her deep masculine voice.