Using an anal pump to stretch perineum

So it's suggested that you do perineum massage starting at 37 weeks to prevent tearing during labor. I'm coming up on 38 weeks and absolutely couldn't comfortably reach my vajayjay to do my own massage. I tried to get my S/O to do it but the damn dork thinks his penis should be good enough. I have to remind him that although he may be well endowed he isn't as big as a newborns head! I swear I don't know how this man trapped me lol. So instead of waiting around for him or breaking my back trying to do it myself I bought an anal pump! So far so good. It reaches a pretty decent size. I obviously haven't worked up to that large yet but I'm hoping this will be what I need to stretch properly.