This UberASM changes Red Yoshi's behavior to be similar to what happens in SMM2: Yoshi can't stick out his tongue, but he can breathe fire without needing a shell in his mouth. Normally, he spits out a single straight fireball, but if Mario has the fire power, he'll spit out 3.
Check out the asm file for some customization options.
There was a minor bug where tapping X/Y on the same frame you lose red Yoshi (by taking damage or dismounting) would cause him to stick his tongue out as normal, but this has been fixed by the author. Everything else works as intended, so, accepted.