Has anyone ever come across ?brook (not too sure about spelling) used instead of burp?
I brooked/I burped.
Was that you brooking/burping?
It may be derived from Scottish Gaelic.
Scots Gaelic does use bruchd for "burp". The word may have entered Scots dialectal English as "brook"; I've not come across it (but I'm not Scottish).
The OED has ruck, ruct and but are obsolete and rare, with quotations from 16th to 17th century.
Nall's Glossary of East Anglian Dialect (1866) includes:
This is interesting, it gives variants from Celtic and Germanic languages, although they could each be independently imitative of the sound and unrelated.
English verb, brook
One of the OED definitions of the verb brook is:
It has quotations from c950, to 1598's:
Other definitions include being able to endure something (i.e. to stomach it), or to find something agreeable.
According to etymonline.com, the verb comes from:
English noun, brook
The noun brook means a small stream, but originally meant a torrent or strong flowing stream.
Dwelly's Classic Scottish Gaelic Dictionary (first published 1901-1911) includes:
This is most likely the source of the term you heard.