Pause Button Supports (aka YRCs, V-Trigger Screen Freeze, Time Stop)
If you're new to the community or are a little out of the loop you may hear the term "Pause Button Support" thrown around. While it may seem obvious to those who already know, it can be somewhat confusing to those who haven't yet learned the terminology or details. While there's obviously no dictionary definition, a Pause Button Support is a Support Pokemon that can be used as a pause button of sorts, giving you an extra buffer to react to a situation. This is somewhat similar to a Yellow Roman Cancel from Guilty Gear or a V-Trigger activation from Street Fighter V. Pause Button Supports tend to be the buffing supports, such as Eevee, Togekiss, or Jirachi. Another one, which is very similar to YRCing a projectile in neutral in Guilty Gear Xrd, is Farfetch'd.
They can be a bit iffy and sometimes you may be locked into a punishable state; most buffing supports are 9 frame punishable and due to the long cutscene are easy to react to. A buffered 9 frame move will definitely punish if you're within range. This means that if you call the support too late into a move's startup you'll be punished anyway. Be cautious.
On the flip side, with a bit of a read you can absolutely lock down a more committal option, such as Blaziken's 6A[X] (Enhanced Flare Blitz) and have an absurdly easy time reacting. The reward on these reactions can sometimes be much more rewarding than another support used offensively-say Emolga-in terms of damage and positioning. If you play a character like Mewtwo (who gets around 230 damage on a deep anti air) or Lucario (who can get 255 damage plus a 30 damage wallsplat on a deep anti air with the correct positioning) the reward in this specific situation (Blaziken 6A[X]) can be a huge margin better.
Here is an example of a Pause Button Support call, you can see that the Lucario calls Farfetch'd and is able to react to the Mewtwo's jump much more effectively.
Generally safe times to call support that can net you this effect:
After a Phase Shift from Field Phase to Duel Phase
After burst declare (activating burst mode)
When significantly plus on block
Generally unsafe times to call support that may get you punished:
When point blank to the opponent
Near the end of a move's charge time
When a projectile is nearing contact with your character.