You vill have to sacrifice some convenience. I suggest inverting a wide-mouthed plastic cup as a barrier over the can. Remove the cup when you want to drink, drink from the can, and then immediately replace the cup. Eventually you will drop or knock over the cup. Wipe with the cleanest thing you have available and replace. A little dirt won't harm you. Cheers!

I can think of a few solutions:

1. Stretch a square of mosquito netting over the mouth of the can, with a rubber band to secure it in place.


2. Buy and use a soda can lid.
   


3. Switch to 2L bottled soda and use auto-sealing bottles.

When I was a kid, we had like plastic lids that fit over the top of pop cans, designed to keep out the yellowjackets (wasps that like your sweet beverage). You opened a hinged trap over the can's opening to drink the product. I couldn't find the exact one, but it was similar to this:
(Can Covers)

My Dad drinks canned beverages regularly while working outside, and his go-to solution for keeping wasps/hornets/etc out of the cans is a small disk or square of 1/2" plywood about 4" square (or diameter) placed on top of the can. If there is a gap caused by the tab sticking up a bit then he will remove the tab, but usually the weight of the piece of plywood will press it down. It works, and it is cheap/free if you have some wood scraps laying around.

He has been using this solution for the last 20+ years and in fact has been using the same circular piece for as long as I have re-callable memory. He even uses them when not outside now, for the 'just in case' factor (and probably out of habit). He started doing this because somebody he knew accidentally swallowed a bee, was stung in the throat and unfortunately did not survive.

This happened to me, but with a brick of pineapple juice instead of a soda can. Lucky for me, I'm not allergic to anything, but I still had to get a methylprednisolone shot just to deal with the inflammation of my tongue.

In my experience, wasps will bother you if you have sweet drinks anywhere near you, no matter what you do. Even if you keep every bottle and can capped, when you drink or move them around, small micro-drops will fall here and there -- enough to attract all wasps in a mile.

They will also bother you if you have food, or other drinks (sweet or not). Also if you are drinking water in a hot day.

Also if they feel like it, mostly.

I've sometimes tried to make a small puddle of juice a few steps away from where I was eating. Some call this a distraction so wasps are attracted to the puddle instead of my beverage. Some call this an offer to the Wasp Goddess hoping She will spare me of Her wrath. It doesn't matter what you call it: it doesn't work. The wasps will just call more wasps and make turns so they can drink from the puddle and keep bothering you at the same time.

My main recommendation is that you restrict yourself to drinking water (soda is bad for you anyways), and to use only capped recipients: bottles, canteens, maybe those cups with a lid and an orifice for a capped straw. If the recipient is made of a clear material that allows you to see if a wasp managed to get in, that's even better.

If that doesn't work, pack up your stuff and move somewhere else.

If that doesn't work, just remember that wasps are attracted to wasps' carcasses. Once you get one, it's like shooting fish in a barrel.

Presuming that you have a modern can, the simplest solution I can think of is to rotate the ring-pull 180 degrees around its axis, so that the lever is over the opening (as per the image below, but without the straw). This may not be an infallible solution, but it should reduce the probability of a bee entering the can, and still allow you to drink in a relatively unhindered manner.

Take a pen or fork and jam/poke it at the top of the can where the tab is connected to the top of the can. See diagram below:

I've done this almost my whole life, it would look like it would be hard to drink from, but it is really easy. It's kind of like drinking from a sports bottle nozzle. Also if you're feeling a bit adventurous, aim it an arms length away from your mouth and start shaking it.(or aim it at someone else)

Therefore, in conclusion, your bee problem is solved and you have a funner and cooler way of drinking soda :D

I can certainly sympathise with your situation from experience — wasps especially love all kinds of sweet drinks, and will home in on them with monomaniacal persistence. I've even had them try to get in my mouth while I'm drinking from a cup, which can be a somewhat unpleasant situation.

(FWIW, the most important thing to do if there's a wasp or a bee buzzing around your face is to not panic or try to swat it, but just keep as calm as you can and gently guide the insect away, preferably while slowly moving away from any sweet-smelling things that might be attracting it. Remember, the wasp is just looking for a sugar fix — it's not (yet) actively trying to sting you, and will only do so if it feels that you're a threat to it or its nest. Granted, it can sometimes be hard to predict exactly what an insect will perceive as a threat, but flailing your arms around in panic is generally not the best idea.)

Anyway, the best proactive solution to your problem that I know of is to get a plastic bottle with a "sports cap" like this and pour your drink into it (or just buy a drink that comes in a bottle like this to begin with):

^{Photo by Mikael Häggström via Wikimedia Commons, released under the CC0 public domain dedication.}

The closeable cap prevents insects from getting into the bottle when you're not drinking from it. It's also designed to fit in your mouth, and even so that you can open and close it using your teeth, making sure that no bugs can sneak in while you're drinking, either. And even if a wasp or a bee somehow does make it inside, e.g. while you're pouring the drink in, the passage which the liquid flows through inside the cap is narrow enough that it probably won't get from the bottle into your mouth.

(That said, I'd still rather try to keep them out of the bottle in the first place. A transparent bottle might be the best choice here, as it'll let you visually double check the contents of the bottle before taking a drink from it.)

Also, try not to have anything near you (such as exposed food or drinks) that might attract insects with its smell. In particular, rinse out any empty cans with water if at all possible, and clean up any spilled drink. If you must have something smelly around, try to keep it somewhere as far as possible from where you are, and hope that it draws the insects there instead.