What I see Westballz do is double shine, then after you shine the second time wavedash down if you're behind their shield or do a short wavedash behind them if you're in front of it (this eliminates the potential for you to get shieldgrabbed). If they're still in shield, shine again and either keep double shining + wavedashing down, or just mix in a reverse shine grab and throw them for positional advantage/a kill depending on the opponent's weight class, DI, and percentage.
Nonetheless, this type of shield pressure shouldn't be attempted until you have all the basic Falco fundamentals down. I know it looks cool, but you can usually just shinegrab and get something out of it (I'm pretty sure you can buffer roll out during the WD down/behind).