Fingering Advice: Lesbian Couple SOS

So my girlfriend and I are a lesbian couple, and she always fingers me and makes me climax. But whenever she wants me to finger her, she gets uncomfortable so I immediately stop. I don't want to hurt her. But she says she wants to feel what I feel when she fingers me. I always try to start out small and slow but I'm too scared to hurt her. She's never masturbated before, but she isn't a virgin (first time fingering her she gave me her virginity). So is there any advice from others to help? She really wants to know and feel what it feels like to cum from finger stimulation. Are there any techniques? Help.