1. bunk up - Noun
2. bunk up - Verb
bunk up (third-person singular simple present bunks up, present participle bunking up, simple past and past participle bunked up)
(intransitive, informal) To sleep in the same house, room or bed as someone else.
I have to bunk up with Joel, as my landlord has kicked me out.
(UK, informal) A manoeuvre in which one person is pushed upwards by another, or others, in order to climb over a fence or similar obstacle.
Synonym: leg up
Give us a bunk-up and I'll get your ball back.
(slang) Casual sex.
Source: en.wiktionary.orgbunk-up