To perform Solid Snake, Fox, Falco, and Wolf's Smash Taunt, do the following. For Snake, go to the Shadow Moses Island stage, and quickly and repeatedly tap D-pad Down. Snake should crouch down and put his hand to his ear, occasionally nodding and seeming to speak to someone. He will then stand up and a beeping noise will be heard. Then, Snake and one of three characters (Colonel Roy Campbell, Mei Ling, or Otacon) will talk to Snake about the character you are fighting. For Fox, Falco, or Wolf, go to the Lylat Cruise stage, and quickly and repeatedly tap D-pad Down. Fox, Falco, or Wolf will bend down and start to rapidly shake his fist. After a brief period of time, Fox, Falco, or Wolf will stand up and salute someone off-screen. However, nothing will happen until you pass through the warp. Afterwards, Fox, Falco, or Wolf's team will start talking about the fight. What all the characters will say depends on where you are, leading to a total of five different conversations for all three characters. Note: This can also be done with Fox and Falco on the Corneria Melee stage.
Play on the Shadow Moses Island stage as Snake in Training mode and select Falco your CPU opponent. Quickly and repeatedly tap D-pad Down. When Snake kneels down, instead of Colonel Roy Campbell, Mei Ling, or Otacon calling him, Slippy from Star Fox will call him.
Select Fox or Falco. Go to the Lylat Cruise stage. Using the Nunchuk and Wiimote, press 1 + 2. Do this until your character kneels down. This action takes a while, so you may want to do this in Training mode. When he is done he will salute. Soon either Peppy, Slippy, Falco, Fox, Wolf, Leon, or Panther will start talking as if you are playing a Star Fox game. This also works on the Corneria stage, but only Fox, Peppy, Falco, and Slippy will appear. You can also do this with Wolf, but only on the Lylat Cruise stage.