There were nine callouts involving "men with rings stuck on their penises" since April, it said.
The brigade urged adventurous couples to be careful in order to to avoid an "embarrassing" visit.
In the last five years the capital`s fire crews have been called out to:
- 102 incidents involving people being trapped in handcuffs
- 810 rings removed, including 23 instances of men with rings stuck on their penises
- Other incidents including releasing men`s genitals from toasters or vacuum cleaners
Each incident costs taxpayers at least £326 - a total of £830,000 over the past three years.
London Fire Brigade director of operations Dave Brown said: "We`re pleased that fewer people are getting themselves stuck in difficult situations and reducing callouts; however, it seems the Fifty Shades of Grey effect is still leading to some call embarrassing callouts."
The warning was issued upon the cinematic release of the second Fifty Shades of Grey film.
Based on EL James`s trio of hit erotic novels, it follows an affair between student Anastasia Steele and billionaire Christian Grey.
According to BBC Entertainment, the film adaptation has received a "critical spanking" from reviewers.
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