Jet, for example, crossing Peru regularly (5)
I believe the answer is:
spray
'jet' is the definition.
(spray is a kind of jet)
'for example crossing peru regularly' is the wordplay.
'for example' becomes 'say' (I've seen this before).
'crossing' indicates putting letters inside.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'peru' are 'pr'.
'say' going around 'pr' is 'SPRAY'.
(Other definitions for spray that I've seen before include "Drench" , "Aerosol efflux" , "Atomiser or nebuliser" , "Sprinkle water on - a small bouquet" , "posy of flowers" .)