Sounds like you're just not doing it right. Are you getting the L-cancel? Fox will flash if you're doing it right. That's step 1. All that does is allow you to move afterward quickly enough to not get hit by anything. The shine after is what makes it safe. If he tries to grab, the shine will hit him before he's able to grab you. So,So I'm having trouble with the Ness matchup. I honestly don't know how to approach this. My friend simply camps on one end of the stage, and punishes me with a grab. Keep in mind that I try to approach with Nairs and Dairs. I'm still very nooby so I was hoping that I was SHFFL'ING correctly or whatever in order to be safe, but it turns out as I am not as I am easily grabbed out of it upon block. Either I suck, or Nair and dair isn't as safe as I think it is.
So advice for the matchup in general please?
1. SHFFL: Make sure you're L canceling properly.
2. Shine: This comes out quicker than anything he can do out of his shield.
3. Wavedash, or jump, or SHFFL again: If your shine hits his shield because he held it up, you'll either want to wavedash through him for a cross up, backwards for safety, or keep hitting his shield with more SHFFLed aerials into more shines. Keep in mind that doing all of this fast enough to work is very difficult and fatiguing on the hands.