EXCLUSIVE

Trawick's stylist Nik Rae Falco at TRIM in Venice tells TMZ ... Jason's been bummed ever since his engagement with Britney fell apart in January ... so last week, she offered to give him a fresh new haircut to "sex him up a bit."
Nik says Jason replied enthusiastically, telling her he wanted to look good in order to meet girls -- so he gave her free reign.

Not bad, but we still gotta ask ...