Specialist police were called in as a long-time criminal sat in a car holding a razor to his wrist, a court heard.
Burnley Crown Court was told how negotiations with Craig Oldfield (40) took place for two-and-a-half hours, with no effect.
He was then distracted, the vehicle door was opened, and he was tasered and arrested.
The car was searched and officers found not only the razor, but a craft knife and screwdriver.
Oldfield, who had assaulted his partner two days before, leaving her struggling to breathe after grabbing her by the throat, was in breach of two suspended jail terms, imposed in March and June, for theft and possessing an offensive weapon.
The defendant, of Como Avenue, Burnley, had admitted breaching the orders and being found on enclosed premises, common assault and possessing a bladed article.
He had been committed for sentence by Burnley magistrates and was locked up for 38 weeks.
The court had been told assault victim Donna Murgatroyd telephoned police on November 14th, saying the defendant was in a vehicle, threatening to harm himself.
The defendant had more than 40 previous convictions.