I'm pretty sure this is referencing the moment from Roselia's live in which they were performing ONENESS and Aiba-san (Yukina's seiyuu) does exactly that to KodouHaru-san (Sayo's seiyuu). And how Aiba-san is just smiling through it all is absolutely adorable!!
Useless Gay Cluuuuuub! Finally somewhere that my username makes sense LOL
After being is so many disastrous relationships, I agree being single is awesome ^^ But having a girlfriend like Nozomi would bE A THOUSAND TIMES MORE AWESOME!!!