Acronym for one of the following: Slap On Sight, Smack On Sight, or Shoot On Sight. Term originaly appeared in the hip hop underground of the mid 1990's though its use has resurfaced recently. Can be used to describe a threat, to issue a threat, or describe an action in the past tense.
"I'm going to S.O.S. Jaime for what he did the other day." Or "I'm putting an S.O.S. on Andre." Also, "When Jackie saw Olivia, she S.O.S.'d her."