Erotic chap dancing round pole, Tim's rival occasionally (11)
I believe the answer is:
aphrodisiac
'erotic' is the definition.
(thesaurus)
'chap dancing round pole tim's rival occasionally' is the wordplay.
'dancing' indicates anagramming the letters.
'round' indicates putting letters inside.
'pole' becomes 'rod' (synonyms).
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
'tims'+'rival'='timsrival'
The alternating letters of 'timsrival' are 'isia'.
'chap' with letters rearranged gives 'aphc'.
'rod'+'isia'='rodisia'
'aphc' going around 'rodisia' is 'APHRODISIAC'.
(Other definitions for aphrodisiac that I've seen before include "Desire-stimulating food" , "the other driver" , "Love stimulant" , "Food or drink stimulating desire" , "Something that stimulates desire" .)