Sardines without the nasty breath?
My favorite way of preparing canned sardines, which hasn't yet caused me "fish burp", is:


Boil some whole yukon gold potatoes in heavily salted water.
Meanwhile, make a vinaigrette with red wine vinegar and the oil of the canned sardines (assuming they were packed in oil).  I prefer to make the vinaigrette quite acidic.
Toss with parsley and fine julienned shallot and season to taste.
Plate the potatoes smash them into an even layer.
Put the sardines over the potatoes.
Cover with the parsley salad.
Optional: Cover with sriracha to taste.


If there is any credence to the belief that lemon juice will cover up the bad breath, you could alternatively use that instead of the vinegar in the dressing.  Furthermore, the acid from the vinaigrette will help cut through the fattiness of the fish.  Finally, the potatoes will help "dilute" the fishy contents in your gut.