Inflatable probes are one of the best ways to practice sphicter expansion. Inflatable plugs are not of much use here. Probes can have a solid core with a balloon, or a solid outer sheath. The former tend to inflate where they shouldn't -- either outside the bum or deep inside. The latter are the best, but there is a hard limit on how far inflation can proceed, depending on the sheath material. Finally, there are probes without a core, with a similar choice of balloon or outer sheath. They require significant inflation before they are inserted. XXL Inflatable from Master Series does not have a core, and consists of an outer sheath that is similar in feel to artificial leather. I have found that in order to insert the tip, I have to inflate the dong to a significant diameter, exceeding 70 mm at mid-shaft. This dong becomes firmer only if inflated to 75 mm, and only then the adventure can begin. This is quite much, and potential insertors are thus advised to consider this toy only if they can easily insert plugs or graduated bulge towers of girth similar to a standard, 330 ml can. inflated to the maximum, the XXL Inflatable reaches a seriously respectable 85 mm. That is in the upper large category, and should train the muscles to allow the insertor a chance at extra large plugs of 90 mm in diameter. Entry: --------------- Inserting the XXL inflatable can be a frustrating process. It really does need to be pumped up to somewhere between 70 and 75 mm to glide in easily. As such, this toy has a limited audience. It is definitely out of reach for those whould would struggle with a 65 mm solid toy. Once the squishiness disappears, the materials on the sheath will not present a significant obstacle, and the insertor will slide onto the midsection of the shaft without problems -- as far as is reasonable. The only way I have managed to take the XXL inside is by sitting on it. It is too long and too girthy to be handheld while standing up. Inflation: --------------- During inflation, the diameter increases very slowly, maxing out at 85 mm, at which point further pumpings do not contribute anything beyond sub-milimeter increments. This is due to the limitations of the outer sheath material. While balloons can be inflated to 120 mm without trouble during dry out-of-butt runs, they are not as impressive once in. Also, due to the very physics of gas compression, balloons are not very useful for sphincter dilation. The compressed gases relocate by the path of least resistance, expanding the balloon inside and outside the anus, but never significantly at the sphincter. In contrast, solid-sheath dongs such as the XXL inflatable have a limit. Why, 85 mm is barely more than the natural 75 mm when this dong is inflated to assume its natural shape, or the squishy 70 mm when its underinflated and thus easier to insert. True, there is only so far one can inflate with a toy like this. But the dilation is aimed squarely at the sphincter, where it should be, and therefore solid-sheath inflatables are the only toys in my collection which do their job properly. I have wasted enough money on balloons. And if due to the limited range of outer-sheath inflatables like this my progress is limited, so be it. I am thankful as it is for the massive, truly breathtaking dilation levels this dong, and its solid-core (longer and harder) equivalent, theLeviathan (also from Master Series), have already provided. Both of these tools are excellent, but each has its strengths and disatvantages. The Leviathan is easier to insert, but it requires more lubricant, massive amounts of it in fact, and it doesn't inflate as wide as the XXL dong. The Leviathan has a metal valve, while this one doesn't. I love them both though. Deflation: --------------- One thing to keep in mind during inflation is that going back should be slow. It is strictly not recommended to lose girth all in one second. That will overstrain the delicate tissues, and even tear the most delicate parts. No one jumps on anal toys from a height, and thus no one should perform an express deflation. And here is my main beef with this toy. Unlike the Leviathan, this one doesn't feature a medical-style bulb with a metal valve. Incremental deflation can still be achieved, but it is not a slow, gradual process as with a metal valve. For that alone, I lower the ranking. Also, I would prefer to have a longer connector tube: twice as long for best results.