Great question. Wobbling is the best punish you can get, as long as your opponent doesn't mash out before the first headbutt. As Tomber notes in
his awesome guide (you should read it if you haven't already), most people can't mash out of a synched, standing grab on reaction, even at 0%. However, there are some situations in which your opponent might be able to escape:
- You have forward momentum going into the grab. Dash grab, JC grab, or wavedash grab--anything that causes Nana to slide past you--will delay the start of your infinite by a fixed amount of time. JC grab is better than dash grab in this respect, because Nana doesn't slide as far, and recovers from the grab animation more quickly. Still, you'll need to wait a moment before starting the infinite, because if you headbutt immediately, Nana's f-tilt might completely miss the opponent. This delay gives your opponent more time to mash out, so at lower percentages you may need to opt for another grab combo.
- Your opponent is an exceptionally fast masher, or starts mashing in anticipation of a grab. If this is the case, you'll usually need to wait until you rack up some damage before wobbling (~30% is a good rule of thumb, but it depends on how fast they are and how you set up the grab). There are some circumstances where wobbling can be inescapable, though--for example, if you grab an opponent while Nana's Blizzard is out, you can headbutt just after the last hitbox of Blizzard, so that your opponent is continually locked in.
- Nana is not perfectly synched up. This could happen because you had to maneuver around the stage in a way that left her behind, or because she was hit away by the opponent.
Another reason you might choose not to wobble is if time is a factor. For example, in teams, wobbling is not the fastest way to rack up damage, and you may be promptly interrupted by the opponents teammate. Another example is in Ice Climber dittos, where whichever Ice Climber isn't grabbed can interfere.
When wobbling is not possible or not guaranteed, the best thing to do is usually to perform some type of handoff, chaingrab, or combo that will result in an infinite later on. Here are some pros and cons of each:
- Midstage handoff: If you know the timing, there is always a 50% chance (d-throw or f-throw) that you'll get the regrab without your opponent having a chance to escape. U-throw sometimes leads to a platform techchase, and b-throw sometimes leads to a combo or techchase as well. Usually, after successfully getting one regrab, you should transition immediately into wobbling (most instances you see of long, drawn out midstage handoffs are just people having fun/trying to style).
- Handoff near the ledge: This is almost always worth doing, since grab -> immediate d-throw/f-throw is inescapable. The one downside is that Nana headbutts a random number of times, which might give the opponent an opportunity to escape at lower percentages. However, she is most likely to headbutt only once or not at all, and even if the opponent manages to escape, you can punish the breakout animation. You can also jab or f-tilt with Popo to lock the opponent in Nana's grab.
- D-throw d-air or reverse d-air: This chaingrab works against most of the cast. Most characters can escape easily with ASDI (notable exceptions are Falco, Falcon, and Ganondorf who need SDI), but if you hear them mashing, chances are they won't DI correctly.
- D-throw chaingrab: This is another combo that you should almost always use if possible. It works especially well against Sheik, Pikachu, and Ganondorf (in order of effectiveness). One strategy that works well is to chaingrab them until a) they DI in place, so you can get a standing grab into immediate wobble, or b) they DI away multiple times, and you're close enough to the ledge to start a guaranteed handoff. If they're at a high enough percentage that they could jump out/land on a platform, chances are you could've wobbled them without any setup.
- Techchasing: If you're good at techchasing, it's a solid option against fastfallers when Nana isn't present. D-throw and b-throw both set-up techchases on stage, and u-throw can set up techchases onto platforms (or combo into dash attack/u-smash if the opponent isn't going to land on a platform).
