Don't give so many orgasms? That's no fun! (12)

'no fun' is the definition.
The definition suggests an adjective which matches the answer.

'don't give so many orgasms?' is the wordplay.
I cannot really see how this works, but
'so' could be 'as' (eg 'not as tall as me' means 'not so tall as me') and 'as' is found in the answer.
'many' could be 'l' and 'l' is present in the answer.
This may be the basis of the clue (or it may be nonsense).

'that's' is the link.

Can you help me to learn more?