Ergonomic 3D Mouthpiece Design -- 2

I need a 3D design for a mouthpiece intended for oral inflation of a PFD (Personal Flotation Device).

The design should prioritize:
- Ergonomic fit for comfort during use
- Durability to withstand pressure
- Ease of inflation and deflation
- Must be able to fit largest off the shelf silicone duckbill check valve into our custom valve housing

Ideal skills and experience:
- Proficient in 3D design software
- Experience in designing ergonomic and durable mouthpieces
- Knowledge of materials that can endure pressure and are suitable for this application
After NDA signed I can share a concept sketch/design