It hurts, you know, that thing. Um, what do you call it? Kōgan? Anyway, it's an important part for men.
Literal
That [subj-が] painful [copula-んですよ], that [subj-が]. Um, what say [question-の]? Kōgan? Anyway, male [gen-の] important thing [copula-です].
アレ 'that (thing)' used twice as a euphemism — the speaker is too embarrassed to name the body part directly. コーガン (睾丸 'testicles') is the clinical term they finally fumble toward. 何て言うの is the standard 'what do you call it?' hesitation. The repetition of アレが at beginning and end creates a comic framing of embarrassment.