Reverse Universe

Slap and hit people and they won't be pals Slag could be used to describe some gals Parts of a lunch box could include a strap Par for a rapper on stage is to rap Strops have been used on losers in sports Straw could always be used to hide warts Rats only in movies would be a star Rap from me would not be up to par So what about the above has come to past? The first words are all spelled reverse of the last!