Glad to hear that <3
Up until now the trials are the latest content added. Right after you finish them you can read the "EPILOGUE: MISTRESS HELEN'S DARK FLOCK". In any case, after you finish the whole story, you can roam freely and keep exploring around. For next update, you will be able to remodel these locations, and expand the Penitence Dungeon. There will be a rework of this entire location, like I did for the dom routes.
On the other hand, I checked the Ball Gag issue, and it seems there was a small bug that wouldn't let you buy it. I have fixed it already, so you may expect the problem solved for next update :)