Stoppies and wheelies are cool to look at but can be a path to serious pain. You’re putting the bike on it’s nose or tail and are at the edge of it’s performance envelope. IF you attempt a wheelie or a stoppie then you need to be ready to pay the piper–things can (and do) go spectacularly WRONG.
Lots of Sportbikes and Standards will stoppie under EXTREME braking if you’re not careful with body positioning. Floating the rear in the air under hard braking or lifting the front under hard acceleration isn’t that uncommon but it is a sign that you’re pushing the bike pretty hard–so rethink where you are and what you are doing, you might be looking at the need for a track day.
That said, here’s some INFORMATION (not instruction) on how it’s intentionally done: