Tin on tin, these are the shakers we use at the bar.
 
Add cocktail ingredients and ice to the smaller tin.
Put larger tin over and bang together.
Turn upside down and shake with feeling - making sure to keep one hand on each tin so they stay together.
The cold temperature will seal the tins together.
Place on surface and remove top (smaller) tin.
Pour shaken cocktail using hawthorn strainer and/or sieve.