Yes, the compression of the bellows can make a big difference. I’ve taken to using a separate ruler. I don’t really push against the pelvic bone, but instead I flush the bottom of the ruler with the foam comfort ring. Sometimes the length on the Bathmate ruler says 180, sometimes 190, but the external ruler says 7, or 7 1/8” when I start and may reach 7 3/8” by the end of 20 minutes. And for a truly accurate measurement, you should wait 48 hours. I get a 1/4” more in girth after pumping, which only lasted a couple hours when I started, but now last for about 24 hours.
raybbaby