I ended up chatting w/ some friends about stands and what their stomachs sound like so have some hcs of mine
Jonathan's stomach sounds.. Serene. Peaceful. It's not a sound, but as a side note it feels as if you're in a nice English countryside, embracing the mild early summer sun early in the morning.
If you press your ear close enough to his stomach walls you might hear a slight and low buzz, it's not an irritating buzz, more like how a fat bumblebee sounds after she collected a wealth of pollen from a daisy.
Unlike his grandfather, Joseph's stomach is discordant. Bubbly and full of life that makes you feel revitalized and antsy. He's used to squirmy prey but his hamon keeps energizing you to degrees unseen in previous prey of his. His stomach sounds like an old analog TV on a dead channel, occasionally you may hear scrambled speech come through.. Eerie but oddly soothing. It's like someone can't stop flipping channels.
Now Jotaro's stomach is... Different for sure. Star Platinum provides a very prominent echoing noise like an endless cave you're stuck in. All around you is the soothing and quiet sounds of singing. It's Holy's lullabies she sang to Jotaro when he was a bit younger.. He refuses to outwardly admit his adoration for his mother, but Starry cannot hide that raw emotion.
Josuke's stomach is a return to form with how Joseph was, albeit more gentle. Crazy Diamond's unintended healing effect extends to it's stomach, though it is without saying Josuke's stomach has the loudest heartbeat of the Joestars. It's steady and methodic.. The gentle sounds of the seaside can be heard. Morioh is a portside town, after all. Sometimes if you really try, laughter can be heard.
Giorno is less likely to tuck someone away, but on the offchance you end up in Gold Experience's stomach... You'll feel a familiar warmth. It's strange, at times. You'd think that you'd be met with dreariness considering how the boy lived for so long. Yet his stomach is filled with the safest feeling ever... A truly unmarred soul to the very core. He's scarred but still so gentle in the end. Every so often you may hear a distant clock ticking, or 2... Maybe even 3? They don't show up often, as it feels like a dying sound in the end. When Giorno reaches Requiem, the sounds of a belltower ring out, further cementing the sounds of time churning onwards.
Now, Jolyne's stomach is a bit different from Jotaro's as you may expect. There is a noticeable sound of bubbles/fizzing as if you stuck your hand inside foam, or perhaps suds from the bath. This sound is often accompanied by the familiar clean smell of light soap.
Stone Free commonly brings the comforting sound of rain, and a toy xylophone's tinkling. (Idk why I thought of a xylophone... It just feels right)
Misc Characters/Jobros/Jofoes -
Dio has a peculiar sound inside his stomach, as The World is a bit curious akin to a dog or cat putting things in it's mouth. Often you can hear a very slow and delayed heartbeat beyond the methodical ticking of a clock, and the many gears that turn the clock hands inside, unseen but ever moving. If he has recently fed off another, there is a constant sound of faint sloshing and gurgling.
Kars is rarely known what his stomach sounds like, as he doesn't often let people live to tell the tale. Though those who have been spared a grim fate have noted that there's a pleasant humming in a long forgotten dialect.. Others have mentioned the sounds of blood coursing through the pillar man's body.
On the flipside, Kakyoin's Hierophant Green provides a strange experience inside the redhead's stomach. An electrical current often is felt when touching the walls of his stomach, the crackling and sparking fills the air and your ears with vigor. As you fall asleep, you may hear the clink of gems, or the sounds of rushing water through a brook.. And the sounds of a deer scare, almost as if you were in Japan. Safe. And with Noriaki.