A conjunction of the slang word 'twat' (essentially meaning vagina) and 'sausage' insofar as a sausage resembles the most prominent part of male genitalia. The combination of the two words implies its function. A twat sausage goes in a twat, and out, and then back out again ad infinitum.
'Oooh - my twat sausage appears to have been stricken with rigor mortis'
by Logistikon December 10, 2011