This could definitly be a fun activity to introduce at the academy.

Safety concernes: Latex - Exposure to latex in a pourous enviroment such as a vagania or anally is something you should be very cautious with. So best advice is to avoid it. Perhaps having something made, using an alternative latex product. Natural type of products such as intestines or stomachs of other animals could be something to consider, so long as you know the person does not have an allergy to that particular item. Water is a fine fluid to use, however douching products that are already sterilized would be better to use, as they have already been tested safe in that area of the human body.

Another alternative product to consider could be inflateable plugs already designed to be inserted here, just adapt the pumping mechanisim to insert water rather than air.

Time/length of play: If you are going to attempt this particular activity, compounding intervals gowing in length would be a good approach. First to ensure the person is able to handle it, second to ensure you do not harm anything with the added extended stretching. Same as you would anally with any stretching activity.

Other considerations: Assuming this activity becomes something the woman begins to enjoy, she will self lubercate, and therefore her body may attempt to expell the inflated item. Consider the diamater of the opening, and how to block the expulsion.

Tempratures: The tissues of the inner areas of the body are more sensitive, and therefore more easily damaged. Ice can be used for cold, as it will not cause tissue harm, and melts upon contact. Warm fluids should be approached with caution.

Humiliation factor: When having the person endure this, considerations for where she will be required to wear it, and considerations for what would happen should the wall of the item fail, and the water flush from her body. Work or store this could be a very large problem.

It doesn't sound unsafe, but its not an activity I would approach casually either.

Have fun!

V/R
ID