Once again, the double-ponytail Xiaomeng was wearing her latex catsuit. Arms and legs folded and fixed by cling film, Xiaomeng became a cute latex puppy. At the beginning she was wearing a ring gag in her mouth. However, I suddenly realized that a mask is indispensable for the recent recurrence COVID cases, therefore I replaced the ring gag with a mouth mask. The mask is made of latex, which means its effect of isolation is extremely good. As for the capability of breathing… that’s not under consideration… Next, her fists got wrapped by cling film. Now it is impossible for Xiaomeng to remove any items applied on her by herself anymore. I put a latex hood with only two small holes at her nostrils on her head, and then put a gas mask on top of that. A one litter open-end rebreather bag and a bubble bottle were connected to the gas mask sequentially. Although these two items did not completely close the air path, Xiaomeng soon became exhausted and could not last any longer. I learned later that the small holes on the latex hood were shifted away from her nostrils under the pressure of the gas mask, thus the breathing resistance suddenly became so high that she could not stay calm anymore. Finally, I carefully adjusted the position of the holes, connected her gas mask to the rebreather bag, and blocked the open end of the bag. Xiaomeng entered a closed rebreathing situation. She tried two different gas masks. How long can she rebreathe?