There are different types of Panty Mistressing. It’s a panty flavoured type of BDSM.
Briefly…
Some subs like to be told to wear the panties to work and made to take pics of themselves wearing said panties for Mistress’ pleasure.
Some subs prefer the more gentle style of Mistressing, they like to receive packages of Mistress’ lipstick, or a pair of pretty pjs to sleep in.
Humiliation, being dominated, forced or willing feminisation…
Have you see the sissy section on the forum, there is plenty of info on there.