Perhaps Osamu is slightly nervous about this because Akaashi has flirted with him before. So has Bokuto one time before interesting enough.. When they get off the bus and both Bokuto and Atsumu are there to pick them up Akaashi tells his bf how comfy Osamu's shoulders are,, 👁️

Osamu would think that Bokuto would get jealous at the moment but on contrary he looked at Osamu smiling and commented "Is he Ji? I need to try it someday". Having two men flirting with Osamu makes him flustered and Atsumu is very confused looking at whats happening in front of him.😌