vs grab oriented characters like falcon, sheik, marth you have to play more patient than would normally like to play. Keep in mind, those 3 characters play control vs the spacies (and the reason I bring this up is because every character that isn't a spacie will learn how to fight against a spacie as first priority since they're top tier). They're waiting for you to attack, always.
vs sheik in particular, this may sound ubsurd but she doesn't actually have a safe/reliable approach vs you. Grounded Needle? She has lag. Air needle? Don't get in that zone. Dash attack? CC.
So then they'll resort to those fairs, most sheiks do that since they want to test what they can get away with. The answer to those shffl fairs is to simply not be in that position to begin with, getting shffl'd fair'd to jabbed on shield is pretty nasty shield pressure, that's a game u dont wanna play, back off. It's not about "countering" her fairs, it's about realizing that's situation you can't win, it's a stacked mini game in her favor where you will always lose - so don't play the game.
She shields a lot? Ok. Get behind her and start pressuring her. Wavebomb the living hell out of her.
Wavebomb --> jab --> wavebomb ---> jab ---> another attack will break her shield.
If you aren't comfortable with that kind of approach just run away (not too far though, mind your position) and charge a blaster. What's she going to do? If they run toward you as a response, that's awesome because now they're the aggressor and you can wait to punish something.
BUT, and a big BUT is that i just offered two extremes. The option to grab is always there. dthrow bomb nair will work at lower % if they don't DI. Most of the time they'll DI away so then just follow up with a ftilt, it's great reliable damage and is punishing enough to make them realize that shielding too much can be bad. And honestly imo, it's best to mixup those three respones as much as you can.
If you pressure too much, then they might nair oos or find some window of opportunity if you screw up. If you play too passive then they'll put you in worse positions since sheik's offense is threatening. If you grab too much then they'll wait to jump oos and then punish.
/my 2 cents on it
@Pi: Hey buddy see you at apex!
EDIT: Which sheik is it? You're still in BC right? Don't tell me it's Rusty XD lol >_<