Yep. Sorry for the delay T_T
Other then what I already told you about the genjutsu he instructed you correctly with the other stuff. Except that only siblings (according to the SNK rules on here) can be your bio.
Now. The main technique used for SNK clan bios.
(Souma no Kou no Jutsu) Twin Demons Technique
Type: Supplementary
Rank: A-Rank
Range: Short
Chakra: 30
Damage: N/A
Description:
The Twin Demons technique allows Sakon and Ukon to merge and unmerge their bodies together using their kekkei genkai. Typically, Ukon is dormant within Sakon's body, with only his head protruding from the back of Sakon's neck, although he can move freely inside of and protrude any part of his body parts from anywhere on his brother's body. The core behind this technique is the ability to reconstruct and deconstruct ones DNA to merge with anothers. While Sakon and Ukon possess this ability naturally, Kabuto Yakushi was able to copy it to enable him to access the DNA and the abilities and techniques of the other Sound Five Ninjas. Each time Kabuto switches between the abilities of each of of The Sound Five, he needs to activate this ability. Off course Kabutos usage is imperfect but mainly because he's using DNA copies of the Sound Five and not real living counterparts with the same ability. Because of this, he can never let any of the Sound Five unmerge from his body completely, otherwise the DNA material would perish and not function, as it takes its sustenance from Kabuto himself.
Using your chakra and natural born ability, focus chakra into your body and break your body down on the molecular level so that you can freely pass through your brother/sister's body. Once you have some experience you can easily and quickly move through each other, merging together and separating like it is second nature. The inner twin should focus now and break themselves down, allowing their body to pass through the host twin as to not disrupt their body's functions and step out of their body, becoming two separate bodies.