Help me !

 i was 12 when mom dad split. But before that i'd sen mom nude many times, ie, on the beach on holiday, or when dad worked night shift, i remember he'd come into my room at 4am, carry me into moms bed, and mom and i would lie cuddling for hours, both of us naked
i used to toy with her tits, which were huge to me at the time, or just wiggle on her belly (a kind of early masturbation i guess - it felt nice)
i wish i had remembered more of our nude experiences, i was only about six, but sure remember the nude feeling, and wiggling on her
i remember once after an episode of mr. men in the 80's mommy started tickling me, rising my t shirt up.
i giggled , as her mouth kissed me playfully.
happy times
now a little older i want a litle more
i have spoken to my gf abput the situation and she is bi, so willing to hlp me
but where do i start, where do i go beyond just wanking into her panties, or the occasional fingering of her in her (supposesd) sleep ??