Ogle nice boy, one you clasp, finally (3,2)
I believe the answer is:
eye up
'ogle' is the definition.
(to eye someone up is to ogle them)
'nice boy one you clasp finally' is the wordplay.
'finally' suggests the final letters.
The final letters of 'nice boy one you clasp' are 'EYE UP'.
(Other definitions for eye up that I've seen before include "Check out" , "Consider sexual attractiveness of (someone)" , "Examine closely" , "Ogle" , "Look at (someone) appraisingly" .)