Family Ties/Jessica Jacob's Room
Jacob was weirdly happy after dinner for someone who wasn't looking forward to your trip tomorrow. You don't want to be nosy but you really are curious. Of course if he's in such a good mood maybe he'd be willing to spend some time with you!
Ignoring the weird noises you hear from the kitchen you find your way to your older brother's bedroom door. You turn the handle and let yourself in but freeze in the doorway. Jacob is sitting in front of his computer with his penis pulled out!
You silently hover in the entryway, mulling over your options. You're more curious than ever. You like being naked from time to time but if he did too then why wouldn't he just take off his clothes? Maybe he was going to jerk it? But you'd only heard him mention that to his friends before and didn't really know what it entailed. And why his computer? Then again he was always on his computer, so that part was pretty normal...
One way or another you should make a decision. Silently peeking into your brother's bedroom feels a little creepy.