So, below is an image of a Ruby Glow Dusk toy. This is a type of vibrating grinder that you can kinda ride hands-free.
But most of it is fairly smooth and the genital stimulator aspect (highlighted as the clitoral stimulator) has a very basic texture and a sharper curve that might get uncomfortable fast with a penis, tho admittedly that depends on size (not to mention it will lack friction).
ID: A screenshot of the Ruby Glow Dusk sex toy. It's purple with big slopes. One side is ribbed, with the slightly curved tip titled: "clitoral stimulator" and the other, smooth side titled: "Vaginal/perineal Mound"
Whereas below, with the Xymon Grinder, you have something obviously with much more texture, without the sharper curve, that can be tied or placed on whatever surface and you can go to town. It doesn't have a great option for perineal or testicular stimulation but it has a lot of space for you to grind against and a lot of texture for you to play with.
Texture and space to move gives you friction.
ID: A screenshot of a Xymon grinder. It has a raised texture with scales, tentacles and angles of all kinds. It's rainbow metalic colored.
The Starsi Toy, as seen below, is also a good example! It's small, which means there's less space to grind against and it doesn't have an intense looking texture.
But it does have a nice amount of texture, as well as no sharp curves, a flattish design that means you rest it against something and vibration for extra measure, which might well make up for the lack of space to grind.
ID: A screenshot of the Starsi toy. It's shaped like a starfish, with textured ridges and a little face on the top, smiling. There's a cord for charging and it's orange.
With these, you can see some of the more important things you'll be looking for in a grinder. Firstly, you want to keep an eye out for how much actual grinding space the toy has (some toys, like the first, only have a small little bit textured to actually grind against and the rest is just stimulation and vibration or for penetration. A lot of those aren't ideal for people with penises.)
You'll also want good texture if you're looking for more friction (not just ridges like the first one!) It can be great for some (there are even textureless grinders lol) but you want friction and you get that through texture! So whether through tentacles or scales or spikes, make sure your toy has that.
Even with the Sagittifera Squish toy (which I believe is kind of a stroker/grinder combo that I'm linking instead of showing because it is straight up boobs and tumblr already hates me), it doesn't have a lot of texture that will catch against you like some of the others but it does have enough to give a nice amount of texture, space to grind and the boobs squish together to provide extra stimulation!
Keep in mind a lot of smaller grinders, especially the handheld ones, are designed for clitoral stimulation and might not be super comfortable. It depends on your genital size and how you like to grind but that's probably a good thing to keep in mind (especially since they might be harder for you to get good friction with!) (Starsi is an awesome exception!)
But a lot of the grinders with flatter bases, especially those with thigh straps, like Xymon one (or the tentacle one I linked originally!), will be more accessible. And there are some that also offer specific perineum stimulation, vibrator and penetration options if you want.
But those are the things I think it'd be helpful to keep in mind. I've said a shit ton and I feel like maybe I've rambled less than I've been helpful but if you want more advice/more examples, just lemme know! I love discussing this shit and this only refueled my obsessive sex toy research in the best way possible lmao. π
(I am not recommending any of these toys specifically, by the way! I am talking more about their designs than anything else.)
