on the salmon

Definition

Slang

  • adjective (of a male) having an erection. The phrase is a shortened form of the rhyming slang ‘on the salmon and prawn’, meaning on the (h)orn. The phrase was used as the title of an art exhibition in the East End of London by the young artist Sarah Lucas in 1995.
http://www.dictionarycentral.com/definition/on-the-salmon.html