*1. Do a bunch of push-ups* Before walking out to the beach, you'll want to go into your hotel room's bathroom or find an empty room in your condo and bang out a whole mess of push-ups. Whole mess here is relative. If you're looking to get a beach body in 10 minutes, you probably can't do too many more than 10 pushups. Either way: do them.
BOOM! Look at you now all pumped up! Do five more for good measure. Okay, two more.
Now HURRY! Get down to the beach and get your shirt off before you stop being cut! Time's-a-wasting, tubby!
2. Breathe in suck in those abs and now hold it all day. From the minute you take off your shirt to show off the ripped chest and arms your pushups created until when you put your shirt back on and leave the beach, you'll have to hold your breath. Sorry. Oh. One side note: be careful if you pass out. Your arms are probably exhausted from the 12 pushups and will be too weak to help you break your fall.
3. Never sit down Even people who are in shape have little rolls of skin that billow out over the top of their shorts when they sit down. If you sit down, your roll of skin will be a flesh tidal wave, laying waste to the eyes of everyone near you.
4. Don't let anyone apply sunscreen to your body It will appear as though they are kneading a giant wad of dough, hurting the look you're going for here. Also, sun poisoning can lead to nausea and vomiting, and a good run of vomiting will allow you to lose 5-10 poinds.
5. Wear a comically oversized bathing suit If you were overweight, you would fit into the thing, right? But you are thin, so this bathing suit is way too big on you! (This is hopefully what people will think.)
6. Go deep into the water You can't sit down, your huge bathing suit is falling off and you need to go somewhere to exhale for a second. To the water! Deep into the water. Think about it: even the most obese person doesn't look fat if submerged in water all the way up to their eyes. Fat simply doesn't build up on the top of the skull. With you almost completely covered in water, the people on shore could very well think you're a perfect 10!
7. Get attacked by a shark No doubt you snuck some sort of snack out into the water with you. Possibly a Slim Jim or a cheese steak? Perfect. A nearby man-eater may smell the meat and attack you. A shark bite will take off major pounds from your body AND expose chunks of your muscle. That's right MUSCLE. You're going to have a lot of people waiting to hook up with you when you get out of the hospital.