You slither closer to your little brother. "Hmmm" you think. "I know right where I have to be." You move onto his bed and down to his feet. From there you easily slither underneath the blanket and move to his crotch. You carefully slither into the pants of his pajamas and sit tight next to his balls which are visible through his underpants. You collect all your slime and start covering his balls and cock with it. Thomas feels something down his crotch and gives you a little squeeze. "I see you are in the mood" you say as you start to form a thick thread of slime. You say "Here I come Thommy!" And press yourself into the opening in his dick. Thomas makes a little jump out of surprise and grabs his member in pain. "Ahhhhh" he cries. You keep pumping yourself up his member. Thomas tries to pull you out of him, but his cannot get any grip. He is exhausted and falls into his back in pain. He tries to lay completely quiet to reduce the pain in his cock giving you an easy takeover. Thomas braces himself for the finale he knows will come and you force your last slime up his dick.
Thomas gasps, lifts his entire pelvis from the shock and falls back onto his bed onconscious. Your vision turns black. A few seconds later you jump up straight, gasp for air and grab your member. "Wow. That was probably one of Thomas' reflexes" you say in your new voice. You feel your new body up and give your ass a squeeze. "I am Thomas now" you say smirking while squeezing the dick you now own. You walk to the bathroom and take a good look at your new self. "Hmmm... Looking great. As always" you say to yourself and give yourself a wink.
"How shall we celebrate this Thommy?" You ask your little brother in the mirror.