The SI-X Type F masturbation sleeve from ToysHeart is a Japanese-made male masturbator with a textured interior, designed to simulate oral sex. According to the package, SI-X is short for “Sexual Intercourse-X.” Type F indicates a fellatio simulation. Constructed of a soft, squishy material, the SI-X has a closed end, and is designed to be penetrated by an erect penis, while being gripped or squeezed by your hand during use.

EdenFantasys lists the SI-X as being made of latex-free and phthalates-free TPE, a “rubber polymer blend or compound that exhibits a thermoplastic character.” Right out of the box, I was surprised at how soft and cushiony the material was. Glancing at the product pictures, I thought the toy would be firm, so the squishiness was a bit unexpected. With its rose color and squishy texture, the SI-X reminds me a bit of one of those gelatin salads that’s been mixed with cream cheese and blended raspberries...shaped like a cheese log.

I was happy to note that the unpleasant odor I usually associate with toys made of this material wasn’t strong at all. Even before washing the toy with soap and water, I only noticed a very light scent. While the exterior of the sleeve is molded with a light texture and some lines to aid in gripping the toy, the real texture to note is the one that lines the inside. The interior is lined with bumps, ridges and ribs, designed to simulate the inside of a human mouth and throat. The texture was nice, but I think I would have noticed the intricacies more had the material been a bit more firm.

The SI-X Type F is about the shape and size of a hot dog bun; not too surprising when you consider what you’re going to put inside. The toy’s orifice slightly resembles a mouth, but it isn’t overly realistic compared to many toys of this type. With its rounded “lips” and perfectly circular opening, the business end resembles a large pink eye more than anything. The SI-X has a depth of five and a half inches, but the soft material is pretty stretchy. If you enjoy having your entire cock stimulated at once - unless you are very well endowed - the SI-X Type F should stretch without a problem.

An issue for some men will be the closed end. I know a closed-ended toy is supposed to offer more suction or a vacuum effect, but I honestly didn’t notice much of this during use. Because of the squishy nature of the toy, I think I would have preferred the channel be open all the way through. With a softer material, I tend to enjoy pulling the sleeve all the way down over my cock, so the head pokes out the end.

Men whose glans become sensitive during masturbation or as climax arrives, may find the closed end - coupled with a slightly bumpy posterior wall - too sensitive on the head of your cock at times. My own glans become incredibly sensitive as orgasm approaches, so the ability to pop the head out of a sleeve-type toy is usually something I desire. I was a bit more sensitive than usual while I used the SI-X, so I had to retreat out of the sleeve a couple times when things felt a little too intense (and not in a pleasant way). I know some guys love their knobs polished, so this feature should really please you if you’re one of them.

The SI-X shouldn’t take up any more storage room than most sleeve-type masturbators, and it’s much more compact than Fleshlights or Tenga Flip toys. Since it’s not overly realistic in design or color, I think you could travel with it without arousing too much suspicion, but a simple inspection would tell anyone that it’s a sex toy.

The SI-X Type F is entirely a manually-operated toy. Because there are no motors or vibrating parts, you can use this toy in the bath or shower.

The only noise generated by this toy is the sound of lubricant squishing around in the interior channel during use. While the SI-X isn't a silent toy, it didn't make nearly as much "sucking" noise as some of the masturbation gadgets I have used.

Another drawback to the closed end on the toy is that cleanup and drying it out are a bit more involved. That said, I didn’t have any issues washing out the toy before or after use. I will say the interior had a slightly wet feel after cleaning it, so you may want to wash it out in advance to give it ample time to dry.

The TPE material cleans up nicely with soap and warm water. According to EdenFantasys, TPE toys are made of a somewhat porous material, so use condoms if you are going to share it, as it can not be sanitized by boiling it in water. Allow the toy to dry fully before storing it, especially if you're going to place it in a plastic bag or airtight container. While you can probably leave it loose in a drawer, I am keeping mine in a plastic bag, just in case the colored material is prone to leaving stains on cabinets or other toys that might be nearby.

You can use any water-based or silicone-based lubricant with the toy.

The masturbator comes neatly packaged in a plum-colored cardboard box that’s sealed in plastic overwrap. The packaging shows an illustration depicting a cross section of the Type F toy, showing the actual size as well as the internal textures. While there is some very basic English phrases on the box (“fellatio like” and “made from safe materials” stand out), most of the package is printed in Japanese.



While not overly explicit, the box does indicate there is a sex toy inside. That said, you could use it for storage, if you wanted a little more protection than a plastic bag alone would offer. Since the toy is so soft, I’m sure you wouldn’t want other heavier toys or boxes resting on your SI-X.

Packaged along with the masturbator is a one-use sample of Vanessa and Co. lubricant. As it’s packed in a slim foil packet, you’ll want to remember to discard any unused lube, or it will likely fall over and make a sticky mess.

Because of the super-soft material used in this toy, I found it a little hard to penetrate. The closed end made it more difficult as well, as I was unable to pull the sleeve totally down over my cock. Once I was inside, I found the texture to be quite pleasant. For me, it didn’t feel like I was on the receiving end of a blow job, but it was a pretty good experience none the less. Thanks to the soft material, it was easy to squeeze the sleeve and apply pressure on certain parts of my cock. As I mentioned, I experienced some unpleasant sensitivity in the head of my cock as I neared orgasm, so I personally wouldn’t make the SI-X sleeve one I’d use if I wanted to enjoy a long, protracted session. But for a “fast fix,” I quite enjoyed it.