This specific phrase, refers to a popular adult-oriented manga (and subsequent anime adaptation) known for its distinctive art style and "slice-of-life" premise.
To stay truly updated on Shinseki no Ko , fans typically monitor: shinseki no ko to o tomari dakara de na wa upd
None match exactly because the keyword is so niche — likely an amateur web novel with a tiny following. This specific phrase, refers to a popular adult-oriented
: The school only allows Kimito to stay because they mistakenly believe he is a homosexual with a muscle fetish, thus posing no "threat" to the girls' innocence. Kimito must play along with this absurd lie to avoid severe punishment (exile or worse). The "Stay" (Otomari) Kimito must play along with this absurd lie
The string combines what look like Japanese words with seemingly random syllables and the English abbreviation "upd" (usually "update").
(Japanese: 親戚の子とお泊まりだから出れないわ upd)