English translation (please let me know if there are any errors):
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(ムクッ ムクッ)
(THROB THROB)
完成
COMPLETE
ああん!
普段でさえ素敵な先輩に
Oooh!
This makes the already awesome senpai
さらに素敵なモノが・・・
even more awesome than normal...
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(フンッ フウッ フーッ フウッ)
(HFF HUFF SNORT HUFF)
おい・・・お前目ェ キマってんぞ大丈夫か?
Hey... is something wrong with your eyes?
ちんこが生えたひびき先輩はホルモンの関係でめっさドエロい気分にたってしまうのだ!
Hibiki-senpai grew a penis and has become very sexually aroused due to her hormones!
(ハァーッ ハァーッ ハァーッ ハァーッ)
(Haah Haah Haah Haah)
(カチン コチン)
(Ka-ching K-ching)
ぴかり! こうなったら
Pikari! In this situation
合体するしかない!
we have no choice but to combine!
(ハァ・・・ ハァ・・・ ハァ・・・)
(Haa... Haa... Haa...)
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(ゴクリ・・・)
(Gulp...)
が・・・合体⁉
Co... Combine?!
合体だ!
Combine!
釣りバカ的な意味で!
I mean the way a fishing fool would!
は?
Huh?