Terry can't cover the space below him and his slow air drift won't help him avoiding hits. When in doubt, reset to the ledge instead of trying to challenge your opponent's options.

Jump

Due to Terry’s slow fall speed, using your double jump will usually just reset the situation.

Except that now you don’t have a double jump for recovering.

Use it only to jump away when you can get enough horizontal distance to your opponent, or you really need it to avoid the next hit and you are sure you won't get clipped.

Landing

Back air will auto cancel from frames 1-10 use it to land out of tumble close to the ground without going into a tech situation or landing with additional lag.

Examples

CS/PD

Use CS and PD to mix up your horizontal movement. Be mindful of the startup so don't try to CS against tight strings.

cPD's f6 iframes can sometimes be used to avoid horizontal juggles for a reversal. Make sure you use it high enough to get the autocancel. You should almost always prefer the weak version for PD. Not only is it faster, but also has less end lag and allows for more drift.

Air dodge

As with jumping, air dodging too high up will just get yourself frame trapped. Make sure you can land after the iframes end and maybe aim for a platform.

Neutral Air

At low percents, neutral air (f4) can bail you out of non true strings. However, it still doesn't cover your butt and will lose to true disjoints while also being quite easy to whiff punish.

Down Air

This won't actually be hitting the opponent. It has the least end (not landing) lag out of Terry's aerials and specials, so it can be used to quickly get out of tumble. Just make sure your opponent is some distance away.

Drift

Even though Terry has really bad air acceleration, one should not underestimate the importance of the microspacing that drifting gives. You cannot constantly change your drift effectively, but holding in one direction then changing and keep holding into the other can be the pixels that keep your stock from being obliterated.

Also continuously drifting away will give you more time to evaluate the situation before you need to act, instead of staying in the danger zone where you need to buffer an option.