It isn't the most comfortable thing but as long as the Sonographer is gentle and uses lots of jelly it makes things much better! In fact, once I started having the vaginal ones done; I hated the belly ones! The belly ultrasounds are what hurt me because they were always pushing so hard on my belly to get a better scan of the baby. Vaginal ultrasounds are more accurate and closer to the baby, so it's easier on you.