for a first baby, there are some studies that support it is of benefit to do (i'm sorry, but i do not have links for them). however, my midwife is not a big believer of it and thinks it can cause more irritation to the perineal area than benefit. when i had my first, my midwife did discuss it with me, and dh helped me with it, but we were far from consistent and only managed to do it a few times before i gave birth at 37 weeks. i ended up with 2 inner labial "skid marks" that were not bad at all. my perineal floor was perfectly intact and stretched great as dd crowned. i attribute that to my midwife knowing how to support my skin and using hot compresses as it stretched. for this baby, i'm not doing any perienal massage, rather just planning on supporting my skin myself as i stretch to let my baby out, and perhaps using the hot compresses again.