@Annie3434 check out the Silicone Nozzles Model M, it’s pretty close to what you’re describing:
https://siliconenozzles.com/Model-M-Mini-Flexible-Silicone-Nozzle-M.htm
I personally love their “Model Y” which is the exact same shape as the old Klystra “KP” style nozzles that were made from hard Delrin plastic. https://siliconenozzles.com/Model-Y-Flared-Bulb-Tip-Flexible-Silicone-Nozzle-Y.htm
I use the 1.75” Y with a 1/4” bore in “18 - mildly firm” quite often for daily coffee enemas. I also have the larger 2.0” Y in “10 - soft” which is a bit more difficult to get in, but it’s pretty squishy. You might like the 1.75” Y in a soft firmness as it really squishes down during insertion yet provides a great seal, acting as an enema retention plug.
My all-time favorite SNC nozzle for deep enemas is the Model B https://siliconenozzles.com/Model-B-Ball-Seal-Flexible-Silicone-Nozzle-Model-B.htm because it seals against the sigmoid entrance and lets the fluid bypass the rectum, so you can get full higher up without the massive urge to expel. It’s also excellent to use with a massager like the PUREWAVE to really relax and loosen up. I can take 5+ quarts like this.
For a similar idea with smaller dimensions, check out the DBLBL - it still sits a bit inside the sigmoid but it fits in my travel enema kit, so it’s what I bring on every trip and vacation to enjoy daily coffee enemas on the go: https://siliconenozzles.com/DBLBL-Double-Ball-Retaining-Ball-Style-Silicone-Nozzle-DBLBL.htm and again here, don’t be afraid of the slightly larger dimensions, just go a bit softer in firmness and it should fit comfortably. My normal max rectal dilation is about 2”, but I have some very soft SN nozzles up to 2.5” that take some working in, but feel great once inserted.
Good luck, have fun, and please share your findings!