Sho had mentioned about this in his Otonoha, which you can read the translation of the entry here (credits to sumoboy); that he went to Aiba's "Kimi to Miru Sen no Yume" stageplay with Ohno.

In this magazine, Sho mentioned it in two separate segments:

In the main article for individual interview; in regards to recent happenings:

"大野くんと一緒に、相葉ちゃんの舞台を見たよ。終わってから楽屋に差し入れを持ってったんだけど、オレの第一声は「相葉ちゃん！舞台、楽しんでもらえた？」(笑)。そのあとも大野くんと「舞台、疲れたねぇ」とか言ってふざけてた(笑)。でも、ホントいい舞台だったから、それはちゃんと伝えたよ。"

"I went to watch Aiba-chan's butai with Ohno-kun, you see. When it was over they held refreshments in the dressing room, but the first thing I said was: "Aiba-chan! Did you enjoy the play?" XD. Then Ohno-kun and I were joking with each other saying things like: "The stageplay was exhausting, right~?" [t/n: they were probably pretending that they were the ones who acted in the stageplay; while Aiba was the one who came to watch instead.]. But since the stageplay was really good, I did properly conveyed (to Aiba) about that, okay."


Then in the regular segment "Idol Theme Park" with the month's theme is "Why?"; Sho took the opportunity to mention about it once again.

「空腹でもないのに、どうしておなかが鳴るの？」
確か歌の文句にあったと思うけど、どうしておなかって突然鳴るの？（笑）Johnny's Web にも書いたけど、大野くんと相葉くんの舞台を見に行ったのね。で、観劇中におなかが鳴り出して焦った。しばらくして、大野くんのおなかも鳴ってたよ。もう、腹に力を入れて、両手でグっと押さえるしかないよね（笑）。

"Why does the stomach rumble even when one is not hungry?"
I'm certain there must be a phrase like that in a song, "Why does the stomach make noise all of the sudden?" XD I have already stated in Johnny's web that I went to Aiba-kun's stageplay with Ohno-kun. Then, while in the middle of the play, my stomach suddenly growled, so I panicked. Not long after that, Ohno-kun's stomach also growled. Really, there's nothing else to do then but to strain the stomach; with both hands pressing on it firmly, ne? XD.


T/N: I have heard of people having the sudden urge to yawn for no reason when they see someone else yawning; but I had no idea that stomach rumbling can be 'infectious'  too.