A/n: This is also inspired by Wayne Family Adventures (if you haven't read it then go do that because I love that webtoon, but also if you haven't then you can still read this dw). Context for this hc is that in episode 74: Lesson Learned, it shows that Dick was banned from fighting Poison Ivy temporarily when he was Robin because he kept getting eaten by one of the plants (on purpose after the first time I think).
Dick wasn't the only Robin to be banned from fighting Poison Ivy. That was just one of the 'rite of passage' kind of things that all the Robins go through basically.
For Jason, he got banned because he kept making too many bad plant puns to the point that even Batman was grateful when Ivy made a vine grow as a gag over Robin's mouth to get Jason to stop talking. After they got back to the Cave, along with being benched, Bruce tells Jason that he's banned from talking to Dick too (but he doesn't tell him why; Bruce just is scared that Dick will encourage Jason seeing as he's had his fair share of Ivy mischief).
Obviously Jason doesn't listen and calls Dick later anyway (because he's rebellious and also he doesn't understand what Dick has to do with anything) and he vents about being benched when he basically did nothing, just "helped their humour". Dick just laughs and asks Jason to tell him the best of the puns, which Jason does. He also tells Dick that Bruce refused to un-bench him even though he promised to make better puns.
When Tim becomes Robin, he also fights Poison Ivy. He's more serious with it, but he accidentally touches poison ivy or another poisonous plant and wouldn't start sneezing. He starts getting a really bad allergic reaction and he's swelling up but he refuses to stop fighting. Batman's literally holding onto Tim's cape to stop him from falling over, and because Tim's the third Robin, Ivy's used to it by now and just gives up at that point. She grows an antidote plant before just leaving, telling an exasperated/apologetic Bruce to get his kids in order and that she'll be back next week or something.
Bruce is just so done too, so he just lets Ivy go and benches Tim until he gets better.
Tim calls Dick to vent about being benched and Dick can't help but laugh and say that Tim's passed the tru Robin initiation rite.
At this point in time, Red Hood isn't on outright hostile terms with them - or at least not with Dick - but they're not on the best of terms either. Either way, Dick still calls him after he finishes talking to Tim, and Jason just lets it ring out. Dick leaves him a voicemail and Jason listens.
"Hey Jas- Red Hood. I don't expect you to pick up. I don't know why I'm even really calling you a nd I don't want to start anything, but I just wanted to tell you that the Robin tradition of being benched from fighting Poison Ivy continues! I don't even know if you remember - it was a stupid thing anyway - actually this whole thing was stupid, you probably don't care, I know you don't like Tim or remembering your time as Robin - "
Jason just rolls his eyes and picks up because he hates it when Dick starts rambling.
"Spit it out, Grayson, what did he do?"
Dick's just kind of in shock because he wasn't expecting Jason to answer. Like at all. "Jason?"
"Don't. I just wanna make sure he carried on the legacy properly."
Dick is still in shock but he just breathes out a laugh and tells Jason. "He accidentally fell into some poison ivy and had a really bad reaction but he kept trying to fight and only fell into more poisonous stuff. Apparently Ivy just up and left after taking pity on him and growing an antidote. He wanted to keep fighting, but Bruce tried to stop him and failed so Ivy herself literally grew vines around him to help B out."
Jason smiles, and he doesn't admit it but he does remember his own fight with Ivy that got him benched. He still doesn't love Tim, but this did help his image in Jason's mind. After Dick's done telling the story with all the little details, Jason just nods and because Dick can't see him nod, he has to say something so he just says like one word of approval then cuts the call. He's in a better mood for the rest of the night though.
I didn't originally have an idea for why Damian got benched, but then I got it.
Damian just straight up sympathised with the cause Ivy was trying to defend and Bruce had to bench him before he sided with their literal enemy in this moment. When Damian comes back up from the Cave, pissed at being benched, it's to Tim, Jason, and Dick with a literal party ready as a final "You're a true Robin now!"