Opened up and had wild fun with the senior man (8)
I believe the answer is:
unfolded
'opened up' is the definition.
'unfolded' can be an answer for 'opened' ('unfold' can be a synonym of 'open'). I am not certain of the 'up' bit.
'had wild fun with the senior man' is the wordplay.
I cannot quite understand how this works, but
'had' could be 'd' (I've seen this in other clues) and 'd' is located in the answer.
an anagram of 'fun' is 'unf' which is located in the answer.
'man' could be 'ole' and 'ole' is located in the leftover letters.
A single letter 'd' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'and' is the link.
Can you help me to learn more?
(Other definitions for unfolded that I've seen before include "developed" , "Revealed; spread out" .)