乱パ is read as らんぱ (rampa) and means sexual orgy.
らんぱ
rampa
らんよう
abuse
らんぼう
rape
みだれる
to lapse into chaos (due to war, etc.)
みだす
to throw into disorder
らんざつ
disorder
らっぷ
boisterous dance
らんりつ
standing (for election) in (excessively) large numbers
らんばい
underselling
らんぱつ
random firing
らんちょう
confusion
みだれ
らんにゅう
intrusion