"to lose your bottle"
definition: bottle- nerve; courage. So if you lose your bottle, you have lost your nerve and if you bottle out of something, you give up an attempt at something after losing your nerve. However you can also have a lotta bottle, especially after a few drinks.
origin: the most likely source is the earlier slang phrase 'not much bottle', or 'no bottle', i.e. 'useless; no good for anything'. This usage is recorded in a glossary of 19th century street English slang The Swell's Night Guide, 1846