Sit on mud awkwardly and get off (8)
I believe the answer is:
dismount
'get off' is the definition.
(I know that get off can be written as dismount)
'sit on mud awkwardly' is the wordplay.
'awkwardly' indicates anagramming the letters.
'sit'+'on'+'mud'='sitonmud'
'sitonmud' is an anagram of 'DISMOUNT'.
'and' is the link.
(Other definitions for dismount that I've seen before include "Get off one's horse" , "Cease to ride" , "Get down, from bike or horse" , "Get off a horse/bicycle" , "Alight from a horse or bicycle" .)