What Makes Murase Ayumu and Uchiyama Kouki Grow Closer?

(Subs may not entirely correct! Feel free to point out the mistakes/missing translation.)

Uchiyama Kouki's 30th birthday is on 16th August! ヾ(≧∇≦*)ゝ

This clip was from 2017. By that time, they've worked together for HQ, Battery, Show by Rock, Magus' Bride, YOI, Altair and probably Devilman too?
I'm not sure if I explained well but the summary is Ayu and Ucchi get along well because they like to talk about things that considered bad by others. ^^

NOTES:
#1 Radios and dates as shown on the top left of the video.
#2 *Kulak is like an informer in the setting of this story.

CONTEXT:
#1 In Ep.5 of the radio, they talked about the borderline of sharing food with close same-gender friends. Ayu revealed that Hamano Daiki said he's fine with even chewing gum?! But apparently it was lollipop, not chewing gum.
#2 In Rajikyuu #70, Kaito was impressed by the speed of Ayu calling Uchiyama-san, 'Ucchi'. Ayu said he personally asked if it was fine to call him, 'Ucchi' and received an okay. Kaito is jealous lol.

P/S #1: Ayu sounds so soft in the birthday song that I wanna cry. T^T
P/2 #2: I'm dead tired and I don't think I can come out with a video for HQ day. orz
P/S #3: Oh, you're still reading? I hope you have a nice day! =D
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Murase Ayumu (村瀬 歩) / Uchiyama Kouki (内山 昂輝) / KENN
Ishikawa Kaito (石川 界人)

Mention:
Hamano Daiki (濱野 大輝)
Kakihara Tetsuya (柿原 徹也)