I can say from experience that butt plugs are an excellent tool for disciplinary and punishment purposes; not to mention that they're always a wonderful addition to any submissive/bottom's wardrobe! My Mistress makes me wear a locking butt plug harness with a medium-sized plug inserted for about 8-10 hours every day (aside from the occasional day's break). Having my butt plugged on a regular basis is a discreet reminder of my status as Mistress' property and acts like an invisible collar of sorts... it's much more challenging to act out/misbehave when your ass has been stuffed and made off-limits... hmmm!
Particularly effective punishments involving butt plugs that I have endured include:
-Enforced butt plug wearing (consensually, of course) for extended periods of time. (e.g. a standard over-night or 24-hour wearing, and potentially lengthier episodes depending upon how strongly my behavior is in need of correction... my personal longest time Mistress has kept me continuously plugged was 10 days).
-Mistress reserves the right to order me to insert a plug directly in Her presence, as well as bending me over and sliding it in place for me. Sometimes when Mistress deems that I need further punishment, She likes to lock on my butt plug harness and restrict my bathroom usage to short, permitted (and possibly supervised) comfort breaks only.
-Replacing the medium-sized butt plug I usually wear with a large punishment plug whenever, and for however long, Mistress desires.
-Sleeping with a plug inserted until my harness is unlocked the following morning.
-... I have several more examples I could continue on with but to help keep this post shorter, I would be happy to share more punishments
"Also, she says that her Ball Gag is not severe enough-she wants punishments to be harsh enough to remind her not to do it again."
-Whenever I've made the mistake of disrespecting my Mistress verbally, She straps a ballgag tightly in place and locks it on for an extended period that depends upon how severely I misspoke... for failing to address Her by the proper title might be a 15-minute excursion while knowingly disrespecting Her (as all boyfriends and husbands have done at some point or another lol) did result in having to wear a very restrictive trainer-type ballgag head harness for several hours.
-On a lighter side of things, I am gagged while doing chores around our home with the knowledge that Mistress will keep it on me until all the tasks are completed to Her satisfaction.
-Once while we were traveling on vacation and I ended up getting a little snippy in my tone with Her... as a result, Mistress locked my ballgag on and covered it up with a large scarf before bringing me in public for a lovely (and humiliating!) autumn walk.
"Any Ideas for making the punishments worse/harder?"
-I would like to mention that being filled with an enema prior to having a butt plug inserted is a nice little twist of humiliation...
-Chilling a butt plug and/or a ball gag in the freezer before having it used on you is quite the extra touch.
-... hmmm so many more ideas are flooding my mind ;D
I apologize for the long post and would like to thank anyone who takes the time to read this.