Have you tried tentatively tittylicious?

You can always lean heavy into how these breasts affect your main character’s world. How does he relate to these breasts? What do they say about him?

Are they “fun bags” for his pleasure? Are they “milkers” to provide his nutrition and/or human growth hormone? Can he only view them as “chesticles” and thus an extension of his own biology?

Or maybe you want him to sound super smart and you could call them “anterior thoracic adipose-glandular prominences?”

Or maybe you want a serial killer vibe and go with “swollen fat pockets for leeching infantile parasites?”

Or go woke and something like “mobile reservoirs of culture trauma?”

Show, don't tell.

Just a quick idea...

She never wore a bra since the ones in her size were so very expensive. I could hear a loud clap clap clap of noise and see the swinging movements in her shirt, as she ran up the stairs. Once she got to the top, she leaned over, hands on her knees to catch her breath. As she leaned over, the deep v of her shirt revealed a small bead of sweat rolling down her cleavage for what seemed like forever. She stood up and her pink gumdrop nipples strained against her thin, white t-shirt as she breathed heavily.

Honkers. If she’s got a real big set you might upgrade that to Badonkers or even Dobonhonkeros.

Mountains of supple flesh

Just don't put any of those boob people in your story. They're not usually needed anyway.

As a large-chested person who is otherwise petite, I have experienced many different responses. These have included “holy shit look at that” and “Could uou jump up and down for a few seconds” to the far more clever “I bet you can’t touch your thumbs behind your back”. 

I am suggesting here that you show, don’t tell, the bodaciousness of the breasts, via reactions from observers. Their awe and inability to look anywhere else but at the character’s chest area would go a long way towards creating a mental picture for the reader. 

Just name your FC "Ample Bosom" or something that sounds very similar like "Amber Blossom", people will understand.

She breasted boobily across the room

High-yield, high-bounce aestheticial assets. Front-tacklers, eye-lockers. Or background-bluring attention spots.

She breasted boobily down the stairs. Her honka badonkas were like giant balloons, threatening to float away at any moment. 🎈Her melons were meloning, it was impossible for her to find a bra that fit, so her flesh was sensually overflowing from it, like water from a fountain~ ⛲️ You could tell just by looking at them (respectfully!), that they honked if you squeezed them, and because they were perky, you could tell she was a virgin.

Obviously her boobs boobed boobily

They're called Boobed Americans.

You could always go the literal route and use measurements. "Her right boobie was 27” across." For example. Make sure you stay respectful and use good wholesome words such as my example with 'boobie'! 'milk sac as yet unused, her children will eat well'

Boobiddybabbiddybabaddibaa

How about the term "sweater kittens"? It is wholesome and cute, unless someone can't feed them and has to throw them in the river and has to use a sweater instead of a sack.

Have you tried describing without telling?

For example, I once heard them compared to “bags of sand”. I think this will help your writing tremendously! Good luck OP!

Or maybe not mention them at all? Just a thought. If it's not part of the plot, why do you need to discuss them?

You gotta think in terms of firm balloons, my friend.

I'd write more, but I can only write so much with one hand.

“Boob person” is inclusive woke talk that is disrespectful to real she/her female specimens.

I’ve gotta go with the “show, don’t tell” folks on this one, but with a twist: rather than focusing on reactions from others or implying size situationally, why not focus on your “boob person’s” impact on their environment.

Bang! “Goddamnit!” cursed Boobella to herself under her breath, “If I knock over another candlestick or wall torch while trying to sneak past guards, I’m gonna…”

“Ouch!” roared Blorfin Balsashield, her dwarven retainer as he rubbed his jaw and spat out a hunk of tooth before levering himself off of the tavern floor he’d found himself on after Boobella’s massive breastplate had caught him under the chin when she stood from the table where she’d been feasting.

“Sorry, Blorfin!” she giggled, looking down on his prostrate form, “Maybe you shouldn’t stand so close to me while I’m eating.”

Have you considered consulting the Oracle of the Breastriary at Nippopolis? Or climbing Mammary Mountain for inspiration?

She tittidly tittied down with a tittily manner

Just write!

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.