sit on → κάθομαι πάνω σε, δεν μαρτυρώ, δεν αποκαλύπτω, καταπνίγω, θάβω, συμμετέχω ως μέλος, συμμετέχω σε επιτροπή, είμαι μέλος επιτροπής, βάζω τα δύο πόδια σ' ένα παπούτσι, βάζω στη θέση του, βάζω πόστα, επιπλήττω, τη λέω, τα χώνω, τα ψέλνω, ψέλνω τον εξάψαλμο, σνομπάρω, διεξάγω επίσημη έρευνα, συνεδριάζω προς εκδίκαση υπόθεσης, ερευνώ αίτια θανάτου, το λιβανίζω, καταπιέζω, καταπνίγω, ακινητοποιώ, περιορίζω, δένω χειροπόδαρα, κάθομαι και το κοιτάω, δεν κάνω τίποτα, δεν κάνω τίποτε, κλωσάω, τα κλωσάω, κάθομαι και τα κλωσάω

[spiros]

sit on → είμαι μέλος επιτροπής, βάζω στη θέση του κάποιον, σνομπάρω, ερευνώ αίτια θανάτου

If you say that someone is sitting on something, you mean that they are delaying dealing with it.
https://www.collinsdictionary.com/dictionary/english/sit-on

sit on
The cat sat on the mat.
(idiomatic) To block, suppress, restrain.
The chairman sat on the report until the end of the legislative session.
(idiomatic, informal) To restrain (a person).
He started to act up, but she sat on him.
(idiomatic) To take no action on.
I sent the boss my proposal three weeks ago and he's been just sitting on it.
To be a member of.
He sits on the appropriations committee.
To hold an official inquiry regarding; to deliberate about.
To have but not actively use
sit on - Wiktionary

sit on someone
Subdue someone, typically by saying something intended to make them uneasy or embarrassed.
‘someone should have sat on him when he was young’
SIT ON English Definition and Meaning | Lexico.com

sit on
1: to hold deliberations concerning
2: REPRESS, SQUELCH
3: to delay action or decision concerning
4: to wait or be ready for (a specific pitch) in baseball
Sit on Definition & Meaning - Merriam-Webster

Translation blunder: she's going to sit on you → θα κάτσει πάνω σου