-Gintama is about to end in the main magazine, so he wants to thank Sorachi for the big impact he’s had on Ooishi’s life as a mangaka.
-He wonders what makes an excellent manga. Some say popularity or sales, but he personally thinks it’s the condition of the manga and what you can learn from it.
-He wonders just how many people learnt new things and likely had their lives changed by some of Gin’s dialogue, or Sorachi’s comments.
-Eg, in a Oneshot called "Shirokuro" Sorachi published before Gintama’s serialisation, the main character had a line that said “You add soy sauce to Natto after you mix it”. The day after reading this, he added soy sauce to his natto after mixing it. He then realises that that was a crappy example and had nothing to do with Gintama lol.
-Even when he was still an unknown newcomer, Sorachi did a bunch for him like teasing him in Gintama (Volume 20), allowing him to read drafts, and getting a character that resembled Ooishi in the anime (Episode 135). Some even came to know about Ooishi through reading Gintama, and in particular, Sorachi’s mention of him during the Quick Japan interview which brought him to tears. Although he thinks it's an exaggeration to say he is who he is thanks to Sorachi despite this.
-Given how much Sorachi has teased him, they’ve only met 3-4 times, and they only really had a solid conversation one of those times.
-A story from 10 years ago: when returning from the wedding of Oonishi, his first editor that they both shared at the time, Sorachi said to Ooishi “Wanna get something to eat? I’ll treat you”. This was before Inumarudashi was serialised, and he didn’t know many other mangaka, so the fact that not just any mangaka, but a successful one took him out was a big deal.
-Not wanting to waste the chance, he intended to ask about what Sorachi thought was important as a creator, manga arcs, the secret to gags, ect. But in the end, Sorachi just had a nice chat with him. But he doesn’t remember much since it was over 10 years ago.
-HOWEVER, there was just ONE thing he never forgot. One thing he would always remember.
They ended up splitting the bill.
I also went and looked up the references for those interested:
Volume 20: Maison du Auk is a reference to Ooishi’s first manga, Maison du Penguin, which ran for 62 chapters in 2006-07
http://prntscr.com/kq2axn
Ep 135: The “Oo” in Ooishi means “big”, so they’ve replaced it with the sound for “small” being “Ko”, hence Koishi.They also did the same with their editor, who is called "Konishi" in the episode.
http://prntscr.com/kq27yw
Couldn't work out how to embed images, so sorry for the links.