Lincoln: "(Thinking)Well, Lori probably dating with Bobby, Leni still working at the mall, Luna had a gig with her bandmates, Luan is out for a show, Lynn is having her soccer game, Lucy is hanging out with her fellow goths at cemetery, Lana currently wandering in the landfill and Lola is having another pageant rehearsal. That leaves Lisa and Lily and I believe they still in their room."
Lincoln went upstairs and went to the Lisa and Lily's room and only to be greeted with naked Rita.
Lincoln: "(Surprised)Mom, why you are naked in Lisa's room!"
Lisa: "(In Rita's voice)It's me Lisa. I'm currently using myself as a test subject for my new aging pills."
Despite her great resemblance to her mother there are some differences such as her hair is brown instead of blonde and she wear glasses. Seconds later Lisa reverts back to her original 4-year old form.
Lisa: "(In her original voice)Fortunately that form only lasted for few minutes. I've been working on pills that change me into a teenager or young adult but no success so far."
Lincoln: "So you are working on aging pills so that you and our underage sisters can have sex with me. You're awesome Lisa."
Lisa: "That was my intention."
Lincoln: "Can you give me some of that pills. I can't wait to impress our sisters and other girls with my adult form(imagines himself as a muscular man in his twenties)."
Lisa: "First you need to strip yourself. Your clothes may not fit with your new form."
Lincoln strips himself naked and eat the pill handed by Lisa. Once he swallowed the pill, his bones and muscles grow uncontrollably. Second later his body stops growing and Lincoln look himself at the mirror.
Lincoln: (In Albert's voice)Oh no! This pill turns me into an old man like Pop-Pop. I don't want to be trapped in this form forever!"
Lisa: "Worry not, brother. That form only last for few seconds."
Seconds later Lincoln revert back to his 11-years form.
Lincoln: "(Relieved)Whew, I thought I will be trapped in that form forever."
Lisa: "I always stay cautious brother, unlike you. By the way I have more experiments today and this time I need your assistance. I want you to provide me with fresh batch of semen and I will help you to extract it."
Lincoln: "I'm always happy to help you Lisa."
Lisa eat her aging pills and turn into 40-something version of herself and start to massage her brother's penis.
Lisa: "How does you feel by getting a handjob from an older woman, brother?"
Lincoln: "It's great and I can't stop fantasizing about mom."
Lisa: "(In Rita's voice)Don't forget to reward me with your cum, sweetie."
Lincoln's penis gets even bigger and harder when listening to Lisa impersonating Rita's voice. Then Lisa starts sucking her brother's penis.
Lincoln: "Wow, Lisa you're really good at this Lisa."
Lisa's head bobs faster and faster. She even 'massaged' Lincoln's penis with her tongue.
Lincoln: "Fuck! Lisa I'm going to blow!"
Lisa: "(Spits out Lincoln's penis)Not yet, sweetheart. Let this thing grow even bigger(massaging Lincoln's cock).
Lisa continues to massage Lincoln's penis until it grows to its maximum size. Lincoln can't stop fantasizing Lisa for his mother Rita giving him a handjob.
Lincoln: "Good grief, keep rubbing it mom."
Lisa: "(In Rita's voice)Come on darling, cum in this cylinder."
Lincoln aims his penis to Lisa's glass cylinder and ejaculates into it. After several spurts Lincoln collapsed on the floor while Lisa checks her cylinder. Lisa reverts back to her 4-year old form.
Lisa: "(Impressed)Wow, you managed to produce about 300ml or 10oz of semen. That is almost as much as average soda can.
Lisa took few sample from Lincoln's semen and examine it under the microscope. There she sees countless of Lincoln's sperm swimming around.
Lincoln: "Wow, I never thought my cum is full with those swimmers."
Lisa: "Now let's see if they interact with Lori and Leni's ovum."
Lincoln: "Hey Lisa, what is an ovum?"
Lisa: "Ovum is a female's reproductive cell, similar to sperm to you and any other men but it have completely different role. Once it fused with a sperm, it will stick to uterus and eventually developing into a fetus and finally a newborn baby."
Lincoln: "I never heard any of this. Mom and dad never say anything about it and the school never taught anything on this."
Lisa: "They should have but given on our society's opinion towards sex and science itself, it is expected from them."
Under the microscope, Lisa see Lincoln's sperm actively avoiding Lori and Leni's ovum instead of fertilizing it.
Lisa: "(Smiles)It appears that my experiment is a success."
Lincoln: "I don't understand."
Lisa: "Your sperm won't fertilize the ovum of women who is biologically related to you, meaning that you can ejaculate inside me, mother and other sisters without need to worry about impregnating them."
Lincoln: "That's awesome Lisa, why don't we celebrate right now?"
Lisa: "Let me consume that aging pill."
Lisa turns into middle-aged version of herself after eating the pill.
Lincoln: "I can't wait to fuck you, mom."
Lisa: "(In Rita's voice)You really are a pervert, sweetie."
Lisa lies down on her bed, spreading her vagina lips and revealing rosy red flesh inside. Lincoln slowly insert his enlarged, hardened penis into his sister's vagina and to his surprise her vagina devours his penis completely.
Lincoln: "Wow, your pussy swallows my cock whole and I'm not even reached your womb yet."
Lisa: "It turns out that the women in our family had elastic womb, able to accept penis almost all sizes. Likely to be genetic trait passed down from generation to generation."
Lincoln: "That's a good news. I can pound you harder and deeper(pounds Lisa's vagina harder).
Lincoln thrust his penis harder into Lisa's vagina while squeezing her large breasts. Lisa's vagina also squeezing his penis tighter than ever. He was pounding her hard but he was going all the way in on every stroke, and it gave her an extra thrill whenever his balls touched her deep down inside, reminding her that every minute Lincoln spent fucking her, his body was producing more sperm for him to shoot into her at the climax. Lisa moaned aloud at the thought.
Lisa: "(In Rita's voice)That's it sweetie, cum for mommy."
He plunged in deep and came hard. As semen flooded out of him and into Lisa, he could almost feel the entrance to her womb bursting open to swallow up the huge quantity of seed that he was pumping into her as he screamed with ecstasy.
Lincoln: "(Ejaculating)ARGH! AHH! AHH!"
After several rounds of cumshots, Lincoln collapsed on his sister's body, gasping for air. His semen overflown from her vaginal lips.
Lisa: "(In Rita's voice)Satisfied now, sweetie?"
Lincoln: "Of course I'm not. Time for the round two!"
Lisa changed her position and all four on her bed while Lincoln pounds her from behind, holding her plump buttocks. Her large breasts swaying as he pounds her. Lincoln let loose and pound Lisa's meaty vagina hard, fast, and deep. Lisa could feel his balls slapping against her buttocks over and over as his cock penetrated her deeper than anything Lisa had ever had inside her.
Lisa: "(In Rita's voice)Don't cum just yet, sweetie. Let mommy taste your cum."
Lincoln removes his penis from Lisa's vagina and aims it into Lisa's gaping mouth. Then fired a big load of cum into Lisa's mouth and loads and load being shoot as Lisa's continue to swallow her brother's semen.
Lisa: "That was a succulent treat and I feel sad for your sperm. Not just they fail to reach its destination but they also will be digested by me(rubs her belly)."
After ejaculating into his sister's mouth, Lincoln collapsed and exhausted, gasping for air.
Lincoln: "Man, I can't take it anymore. I really need to rest."
Lisa: "Don't worry brother, I have a drug to restore your stamina."
Lisa, now in her original 4-years old form handed that drug which Lincoln hastily consume. Then he regained his stamina and strength, back on his two feet.
Lincoln: "Thanks for drugs Lisa, can I have more of those?"
Lisa: "Sure."
Lincoln: "Despite having this amazing cock and balls but I'm still stuck with stamina of 11-years old boy, only able to cum three times the most."
Lisa: "With these drugs, you don't have to worry about it anymore."
Lisa hands the drugs to Lincoln and they hugged each other. Suddenly they heard their mother downstairs.
Rita: "Kids, I'm home."
Lincoln: "Shit, mom is here!"
Lisa put her clothes on while Lincoln head back to his room with his clothes. After he sighed relief in his room, he checks his pants for Ace Savvy cards he signed not too long ago and he couldn't find it. Then remembers that he may accidentally dropped it in the school's restroom after he used the glory hole.
Lincoln: "Dang it, now I'm fucked for rest of my life."