Hi mama! Honestly, hindi ako familiar sa "perennial massage", baka typo lang or different term ang ginagamit nito? Are you referring to perineal massage (yung massage ng area between vagina and anus)? If yes, maraming OBs dito sa Pinas actually recommend it starting around 34 weeks, at a few of my mum friends swear it helped them avoid or minimize tears during labor. The basic tip is gentle stretching with clean fingers or coconut oil, just a few minutes daily, pero definitely ask your OB first kung safe para sa pregnancy mo at kung paano exactly gagawin, kasi importante talaga ang proper technique para hindi ma-irritate lang. Good luck, mama!