Tony put his arm into the opening of Jane's cock and reached Becca's hand, holding it tight and pulling as hard as he could. Despite using all his strength, instead of Becca being pulled out, Tony ended up being pulled in, with his head and torso being quickly enveloped by his little sister's dick.
Jane's erection grew strong, lifting Tony, who was upside down partially inside her member. With the help of gravity, Tony slid further and further inward. Becca tried to hold him and push him out, but she couldn't and he slipped further and further in. Eventually her muscles got tired and she ended up letting go of Tony, who slid all the way down her side, ending up in a dark and tight, but flexible place.
"Don't tell me I ended up inside Jane's balls." Tony said
"But that's what happened. Now we're both trapped inside." said to Becca, who was in Jane's other testicle
"Then we better get out of here." Tony said
"It can't be done, I already tried and I couldn't, and when you reached out your hand I thought you could get me out of here, but instead you fell in here with me." Becca said
"But there has to be a way for us to get out of here. Jane, can you hear me? Please, you have to find a way to get us out of here." Tony said
"Wait just a minute, it feels so good to feel you two inside my balls." Jane said, and a pulse made it clear that she was very excited about this situation "I'm glad you woke up mom. Look here, Tony and his girlfriend are here inside my balls."
"Excellent. Now make them your seed and pour them over me." Penny said, having been completely overcome by the attraction she felt to Jane's cock.
"That's a great idea mom." Jane said
"They can't be serious." Tony exclaimed directly to Becca
"Apparently they are serious, and Jane's will is already taking effect. Pay attention, I'm already melting into cum." Becca said, and with that Tony realized that his body was really getting very soft. Little by little he was losing the feeling of solidity in his body, so he was sure he was melting and turning into cum.
At some point, Tony had completely melted, so he realized that now he and Becca were nothing more than cum, but he remained conscious and could feel his liquefied body moving inside Jane's testicle. He didn't know exactly how, but he could feel that his mother was stimulating Jane's cock.
Unable to do anything, Tony just watched the inside of Jane's testicle (he could now see in the dark now) until he was eventually pulled through an opening that opened and was guided through a tunnel of flesh, where his liquefied body was mixed with another amount of cum, which was Becca, and both were shot from the tip, hitting Penny directly and painting her white. Despite the force with which they were thrown and the impact, neither Tony nor Becca felt pain, but rather a strong sensation of being the orgasm itself.
After Jane's orgasm ended and all of them were spewed out of her balls, Tony and Becca wondered if this would be the end of them, being carried down the drain like disposable dirt, but they realized they could control and gather the material that they were composed, thus forming a body that rose in an apparently human form, but with its body entirely made of cum.
Having assumed humanoid form, both Tony and Becca looked for each other, then saw that their bodies had completely blended and they had both become a two-headed cumgirl.