Why does this happen to my chihuahua?

So whenever he gets too exited like when my parents come home from work or when he's playing with my other chihuahua sometimes he like freezes then he wiggles side to side, and then he drops and starts twitching and it looks like he's about to die and he's like that for a good 2 - 3 mins and when he gets up he throws up white stuff )': can someone pls explain what can be causing this