[1] : WordNet (r) 2.0

slap on
     v : apply carelessly; "slap some paint onto the wall" syn: clap
         on, slam on
see also:
clap on slam on 

[2] : Moby Thesaurus II by Grady Ward, 1.0

50 moby thesaurus words for "slap on":
   add, adjoin, affix, agglutinate, annex, append, attach, bedaub,
   besmear, burden, butter, coat, complicate, conjoin, dab, daub,
   decorate, enamel, encumber, gild, gloss, glue on, hitch on, infix,
   join with, lacquer, lay on, ornament, paste on, plus, postfix,
   prefix, prime, put with, saddle with, slather, smear, smear on,
   spread on, spread with, subjoin, suffix, superadd, superpose,
   tack on, tag, tag on, tar, undercoat, unite with

Slap >> S Words
Slap, definition of term: Slap
slap_pag1.html

Slap On >> S Words
Slap On, definition of term: Slap On
slap+on_pag1.html