Speaking personally, egg whites are some of my favorite ingredients to add to any drinks. They add a brilliant frothy texture to drinks, and in this case, we're using egg whites as our Bubblebeam.
To make the Wartortle, simply make a Squirtle, then before serving, add an egg white to the shaker and instead of stirring, shake the drink for at least a minute to give the drink the desired texture and flavor. The whitewater we've added to the drink through our use of our egg white Bubblebeam adds some heaviness to the drink, so sip slowly and you won't have to use Withdraw later in the evening.
Muddle mint leaves in a glass with fine sugar. Add 1.5oz vodka, 1/3oz sweet vermouth, 1/3oz dry vermouth, and 1 egg white to an iced cocktail shaker. Shake for a full minute to get it nice and frothy. Strain into your glass.