Mine

on 1:INPUT:*:{
  if ($chr(47) != $mid($1,1,1)) {
    if (%weird == on) {
      unset %heh
      .doswap $1-
      .raw privmsg # : $+ %heh
      echo # $time < $+ $me $+ > %heh
      halt
    } 
  }
}
alias doswap {
  window -e @debug
  set %heh2 0
  :loop
  inc %heh2
  if (%heh2 > $len($1-)) { goto ciao }
  if ($mid($1-,%heh2,1) === b) { set %heh %heh $+ p }
  else if ($mid($1-,%heh2,1) === p) { set %heh %heh $+ b }
  else if ($mid($1-,%heh2,1) === t) { set %heh %heh $+ d }
  else if ($mid($1-,%heh2,1) === d) { set %heh %heh $+ t }
  else if ($mid($1-,%heh2,1) === z) { set %heh %heh $+ s }
  else if ($mid($1-,%heh2,1) === s) { set %heh %heh $+ z }
  else if ($mid($1-,%heh2,1) === f) { set %heh %heh $+ ph }
  else if ($mid($1-,%heh2,1) === $chr(32)) { set %heh %heh $+ $chr(32) $+ $chr(32) }
  else {
    set %heh %heh $+ $mid($1-,%heh2,1)
  }
  echo @debug $mid($1-,%heh2,1) 
  goto loop
  ;bp cg dt fv ij mn qk sz 
  :ciao
  return
}
on 1:INPUT:*:{
  if ($chr(47) != $mid($1,1,1)) {
    if (%weird == on) {
      unset %heh
      .doswap $1-
      .raw privmsg # : $+ %heh
      echo # $time < $+ $me $+ > %heh
      halt
    } 
  }
}
alias doswap {
  window -e @debug
  set %heh2 0
  :loop
  inc %heh2
  if (%heh2 > $len($1-)) { goto ciao }
  if ($mid($1-,%heh2,1) === b) { set %heh %heh $+ p }
  else if ($mid($1-,%heh2,1) === p) { set %heh %heh $+ b }
  else if ($mid($1-,%heh2,1) === t) { set %heh %heh $+ d }
  else if ($mid($1-,%heh2,1) === d) { set %heh %heh $+ t }
  else if ($mid($1-,%heh2,1) === z) { set %heh %heh $+ s }
  else if ($mid($1-,%heh2,1) === s) { set %heh %heh $+ z }
  else if ($mid($1-,%heh2,1) === f) { set %heh %heh $+ ph }
  else if ($mid($1-,%heh2,1) === $chr(32)) { set %heh %heh $+ $chr(32) $+ $chr(32) }
  else {
    set %heh %heh $+ $mid($1-,%heh2,1)
  }
  echo @debug $mid($1-,%heh2,1) 
  goto loop
  ;bp cg dt fv ij mn qk sz 
  :ciao
  return
}