@Cloudyfire sorry it took a long time. Work killed me and barely have time to do anything else other than eat and sleep. But this attachment works on the npg meiki stuff. The edges is a bit sharp and putting in is a bit challenging as it is fairly tight. They dont slip out though so thats amazing. Theres fears of it tearing the grip part of the onahole but ive used it for this week and havent seen anything so far so thats good. Just be careful. Im willing to risk a few scratches on the grip since i really dislike holding the onaholes and its floppyness. It fits on the osr and launch. I love it and havent used my fls in a while. I guess its safe to powder up that grip so it doesnt tear is a safe thing to do.
I used the meiki 01 ozawa, eimi fukada, aika, and amami tsubasa. The soft onaholes like ozawa are easier to insert and you can avoid it from getting scraped by the holder. The more sturdier one like the eimi etc. Its a bit of a challenge to get it in.
All in all, i dont regret the purchase at all.
Thanks to @M0SAIC for making this possible and paving a way to use onaholes. Wont hesitate to buy again if ever i break this one and also wont regret buying onaholes as opposed to fleshlights for more variety.