Amy helps for real

"Shhhhh, be calm. Relax. Breath. Through your nose. Like we practiced. Breathe." Amy tried to soothe and calm her best friend, palming and caressing Sarah's cheeks and throat with her hands, kissing her neck tenderly. They had practiced deepthroating in the past, with dildos and strapons, though none of those had been as big, thick and long as Adam's monster.
"Shhh, you can do it!". And it worked. With Amy's soothing help, Sarah began to calm down and to breath through her nose. Slowly, her pain began to lessen as well.
Amy pressed her tits into Sarah's back and placed more kisses onto Sarah's neck.
"Very good, Sarah. Just like that." Her arms reached around Sarah's upper body, and her hands cupped the breasts of her best friend and started to massage them. She could feel the nipples swollen and hard with arousal.

Unknown to Sarah, her brothers sperm was not only delicious, intoxicating and addictive, it also affected her body, transformed her in small ways. Her throat had been well lubed by Adam's cum, and it made the walls of her throat became slowly more elastic, lessening her pain and helping her to cope with the girth of his monster.

As the pain began to fade, Sarah felt very proud of how much of her brother's cock she was taking. She looked up proudly towards Adam, humming and with big eyes, seeking his approval.