A stock phrase in Japanese pop culture supposedly used by the wife in a newly-wed couple to invite her new husband to bed.

Kyūjitai form of 私生児 (“illegitimate child”)

to hide, to conceal

that which is hidden / that which is protected from outside / (clothing) pocket

(adverbial particle, dismissive, derogatory) emphasizes disgust, contempt, or otherwise negative feelings of the speaker: whatever

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

What? What did you say?

whatchamacallit, X