A man who turned up at hospital with a ring stuck on his penis had to be cut free by 10 firefighters, according to new data released.
It took firefighters 20 minutes to remove the ring after staff at Queen Elizabeth Hospital, Woolwich, were unable to prise it from the man's genitals.
Two fire engines were dispatched to perform the delicate procedure, which took place on the evening of May 1.
There were three incidents in one year in which firefighters were called to remove a ring stuck on a penis, it was revealed in London Fire Brigade statistics covering April 2010 to May 2011.
The disclosure is one of 417 incidents attended by London's firefighters over the last year involving people stuck in objects, machinery and furniture not including road traffic accidents.
The calamities included a man who became stuck in a child's toy car in Kingston-upon-Thames; a youth wedged in an ironing board in Bromley; a person with their fingers stuck in a DVD player in Barking; several children with toilet seats and potties stuck on their heads; and 36 people trapped in handcuffs.
The removal of rings from fingers accounted for 160 incidents, while 74 people had "other" objects removed. 133 people had become trapped in or under machinery or other objects, and 14 people were impaled.
Dave Brown, the brigade's assistant commissioner for operations and mobilising, said: "You wouldn't believe some of the incidents we're called to deal with - people manage to get themselves trapped in some very weird and wonderful places - but there is a serious side to this.
"These incidents are time-consuming, costly and take up the precious time of our crews who are then unavailable to attend other, potentially life-threatening, emergencies.
"We'd ask the public to take greater care to avoid getting themselves into these often ridiculous situations and to think carefully before dialling 999 and calling us out if there isn't an emergency."