Nurse, occasionally I'm tense on a little horse and trap (6)
I believe the answer is:
enmesh
'trap' is the definition.
(I've seen this before)
'nurse occasionally i'm tense on a little horse' is the wordplay.
'nurse' becomes 'en' (abbreviation for enrolled nurse).
'occasionally' means one should take alternating letters.
'on' is a charade indicator (letters next to each other).
'a little' suggests taking the first letters.
The initial letter of 'horse' is 'h'.
'im'+'tense'='imtense'
The alternate letters of 'imtense' are 'mes'.
'en'+'mes'+'h'='ENMESH'
'and' acts as a link.
(Other definitions for enmesh that I've seen before include "Involve, as in a net" , "snare" , "Entrap" , "To ensnare" , "Men she changed to entangle" .)