Slap onto - Idioms by The Free Dictionary
slap something onto someone or something and slap something on
to place something onto someone or something by slapping. Tim slapped a sign onto Gary that said "kick me." Tim came up to Gary's back and slapped on a sign.
References in periodicals archive
Summary: Domino pieces rapidly slap onto
the table in the opening salvo.
This comes on top of the so-called disloyalty charges that some banks already slap onto
customers who use other cash machines.
To combat such bruising blows to skin and confidence Laboratoires Garnier have developed an emergency patch to slap onto
the offending pimple.