Possibly a blend of bævre + blære.
blævre (imperative blævr, infinitive at blævre, present tense blævrer, past tense blævrede, perfect tense har blævret)
- to shake or tremble - of a gelatinous material, body fat, etc.
- Frederik rystede på hovedet, så de runde kinder blævrede
- Frederik shook his head, so his round cheeks trembled
