Wie wäre's damit???

let me sleep over it (for a night)

There is the same expression in English. I would leave out the "for one night" though since it is clear that it is the next day when you sleep over it. ;-)

Agree with badhairday!

Dankeschön! Ich denke ich nehme dann "to sleep over it" obwohl "to consult one's pillow" sehr nett klingt!

@ Hein/ Badhairday: Sorry to wade in after Kati' s made her decsion, but are you sure about sleep OVER it? I' d sleep ON it.
Is it an AE/BE thing?

hattonkote: maybe. I would just like to say that I got it wrong with "over", it should, of course, be "sleep on it"!!!
DOH...

"Sleep over" is what my nieces do in my house...

Okay, then I'll take "sleep on it" :-)
However, does "consulting one's pillow" mea the same or is it much more informal?

@Kati: "consulting one's pillow" is colloquial!