I Help You... You Help Me?

I, a man named Diego Perez, may not possess the utmost strength or intelligence, but I keenly recognize advantageous situations. My stepsister Lily Starfire boasts voluptuous curves in ideal areas - generously proportioned breasts and a plump, desirable buttocks. Initially dismissive when I suggest seeking guidance in sexual realms, Lily eventually shifts her stance upon realizing she lacks assistance with math coursework, leading to a mutual beneficial agreement.
In exchange for enhancing my carnal knowledge, I pledge tutoring support in mathematics. See the fortuitous setup? Yet, the atmosphere took a sensual turn as Lily unveiled her ample bosom, prompting my erection, which fueled her arousal. Initiating intimate contact, she positioned herself atop me, her aroused entrance greeting my member as I grasped her bosom during vigorous motions.
A passionate rendezvous ensued, intensifying as I interconnected with her from the rear, causing her posterior to undulate and granting both vaginal and climax. Succumbing to climax, I insensibly ejaculated within her. Though expressing displeasure, I plan on focusing intently on academic support in the forthcoming week.