Step 1 - find an audience to swear at. Ideally your target is 1 or more Estonians (or at least they understand Estonian). Go find some!
Step 2 - engineer a reason to swear. Organic swears are the best, but fake it till you make it.
Anger, surprise, humor - good reasons!
Step 3 - Cut loose with the swearing. The "Combo" button will string 3 swears together for extra power.
Remember, if your target looks too mad or sad, hit the "Too Far" button. They will immediately calm down as you truly demonstrate that you are really, really, really, really, really, really, really sorry.