i see this happening some where in the first or second year for them.
Severus not caring about his appearance, doesn't bother to comb his bed hair. Lily finally having enough of it comes over to help.
and from the look on Sev's face, this isn't the first time....one might wonder if he did it on propose....
Snape & Lily belong to J.K Rowling
alternate title was "bed-head"