ボトルキープ

Wasei eigo (和製英語; pseudo-anglicism), derived from bottle +‎ keep, from the practice of the bartender keeping the bottle at the bar.^[1][2][3][4]

• (Tokyo) ボトルキープ [bòtórúkíꜜìpù] (Nakadaka – [4])^[2][4]
• IPA^(key): [bo̞to̞ɾɯ̟kʲiːpɯ̟]

ボトルキープ • (botoru kīpu) 

1. the practice of buying a full bottle of liquor or other alcoholic beverage at a bar and having the bartender keep the unfinished bottle until the purchaser's next visit

ボトルキープする • (botoru kīpu suru) suru (stem ボトルキープし (botoru kīpu shi), past ボトルキープした (botoru kīpu shita))

1. to keep one's own bottle of liquor or other alcoholic beverage at a bar

Also encountered as a noun followed by をする (o suru):

• あのバーでボトルキープをしている。

  Ano bā de botoru kīpu o shite iru.

  I've got my own bottle at that bar.