But first experiment at the net before putting it into your own service delivery.
At the net put your forearm at net level and parallel to the net strap, with the racquet head at right angles to your forearm.
Now practice quickly turning your hand and wrist such that the racquet head snaps forcefully against the net strap.
Take your time, keep experimenting – and once this feels somewhat natural – toss up a few (rather than tossing down a few) and see how it feels on the serve.
You may be pleasantly surprised!