Kirbycides aren't as effective as they were in Melee, so you shouldn't have much problems with it. However, some tips for a Swallowcide:
If you're still on the stage when you're Inhaled you should try to Break Free immediately. Do this by rotating the control stick and pushing buttons - but be weary of executing a move that can kill you after breaking out (such as Ike's Quick Draw).
If you're off the stage you have a couple of choices. If you think you can Break Free quickly enough to get back onto the stage, then go for it (chances are Kirby can Footstool off your head first if you're Ike). If it looks like you won't be able to get back to the stage then don't struggle. Kirby will drop off the stage and lose a stock at the same time. You'll get KO'd too, but you can at least make sure to take him with you.
If he spits you out under the stage, don't panic. Most of the time you will still have a jump as well as your usual recover methods. The Star Shot will send you under the stage pretty far if you don't struggle to get out of it (don't struggle) and when it ends you will get a floaty boost to use to help recover. You may have to go for the far side of the stage (which also gets you away from Kirby) but chances are you can still make it back up and only take 10% from being spit out. Someone in my crew plays Ike and he can usually survive this from under Smashville and even Lylat Cruise, though Battlefield can give him difficulties because of the protrution hanging from the bottom.
Good luck. Nothing's cheap.