It might be uncomfortable/painful in the beginning aa your nipples is still getting used to the constant “sucking”. I started with the massage function first. Until i am ok with it, then i moved on to the express function. Its a lot of trying to see which is more suitable for you. My sis in law only used the massage function. She finds the express function too painful for her.
Hi mummy, I'm using Spectra S1 too. I start with 5 mins of cycle 70 and then another 5 mins of cycle 38 on each side.