My nephew was staying over at my place again for the first time in a while, and I noticed he'd grown into a much stronger, more mature young man during our time apart. That night, I caught him sneakily glancing at my breasts several times, and I could clearly see the shape of his hard-on even through his pants. Seeing him so turned on made me unable to hold back, and once I returned to my bedroom, I ended up masturbating—entirely because I'd become aware of his lustful gaze.