Size and shape

At a width of 1.4inches/3.6cm at the widest point, the Mark O2 is the largest dildo I own (that I use internally, at least; the Vixskin Tex is bigger, but I use it only for gender affirming purposes). I was nervous about the size, but when I’m in the right mood and with the assistance of lots of lube, I find the full sensation very pleasurable. However, the girth does mean that I can’t insert this dildo in as far as I could with a smaller dildo.


The left side of Mark O2, showing veins

The right side of Mark O2, showing more veins

The Mark O2 comes in 3 stylised skin colors: cream (a pale pink/beige), cocoa (a light brown) and mocha (black). The dildo is all one color, with no variation in the coloring of the head or veins. The design of the dildo, like the colors, is a sort of stylised realism. The head has a fairly realistic glans and urethra, and the shaft has a few subtle veins, but it’s not highly detailed, so if hyper-realistic dildos give you the creeps, this is a good choice.


The Mark O2 is very heavy and dense. It uses Tantus’ dual-density material, which is designed to feel especially realistic…and is also a huge lint trap, as you can probably tell from the photos.

At the time I purchased this dildo, I was like “wow this feels so real!” but I’ve since got my hands on several Vixen Creations products, and let me say, Tantus’s dual density silicone does NOT COMPARE. By comparison with Vixskin or even Vixen’s single density material, the Mark O2 feels like a rock. If you squeeze it, there is a pleasant springiness to the outer layer, but that layer is thin and most of the dildo is composed of a very firm core. The head is also very firm - much firmer than the rest of the dildo, as there is no squishy layer on it - which makes insertion a bit painful, although probably also makes it a little easier than if it were super squishy like Vixskin.

The head of the Mark O2 is made of a glossy silicon. Now normally I’m a huge fan of glossy silicon, but with this toy, I actually find the texture of the head quite draggy and lube doesn’t adhere to it well. However the rest of the toy is made of a beautiful matte silicon that feels soft and slippery as soon as it’s wet. With age, the glossy silicone on the head of the toy has becomes less shiny. It used to really glisten, but now it looks dull except for one small patch. So my photos don’t really show the glossiness well - you’ll just have to trust me that it’s a different texture to the shaft.

The head of the Mark O2 is glossy and has subtle realistic details.

In use

I’m going to say, straight up, that this dildo does not feel like a real penis. In spite of the dual density silicone, it’s much firmer and, consequently, more painful than actual PIV sex. However, I’ve come to enjoy this toy in its own right. There are times when I just want to be roughed up, and this is definitely the dick for the job.

The Mark O2 is uncomfortable for me to insert, rubbing against my urethra and there is a distinct popping sensation when the head passes my pubic bone. But after the initial discomfort of insertion, if I’m really in the mood for that much girth all I feel is a pleasant fullness. With careful thrusting, this toy very quickly brings me to an explosive, satisfying orgasm.

Unfortunately, if I cum on this dildo I need to reapply lube if I want to keep thrusting with it, because that glossy silicone on the head immediately becomes unpleasantly squeaky when my juices wash the lube off.

The Mark O2 isn’t super textured, but the veins and other subtle details, paired with the slightly squishy silicone and the grabby texture of the head, make it more stimulating than a completely smooth dildo, I find. It perfectly balances girth and texture.

I was a little disappointed to discover that unlike my other Tantus dildos, this one doesn’t have a suction base – even though riding it would probably be out of question because of the girth of this one and the difficulty I have with that penetration angle, I am sure this would be a deal breaker for many.


This is not a toy I get out for an everyday wank, but when I’m really horny and desperate for real sex it definitely satisfies me in a way none of my other toys can. For someone with roomier anatomy than mine I can imagine it being perfect, and for me…well, lots of lube and easy does it.