I, and as far as I’m aware, most women need a little respite between orgasms just to lose the sensitivity, maybe a minute. Not too much more for me or I begin to come off the ‘orgasmic plateau’ as they call it.
If he’s gone down on me he’ll know when to pause, and he goes to kiss my pussy more gently, nuzzles a bit, looks up, and then goes again. Super hot.
Just start soft the second time, definitely don’t ruin them!
My other advice though, is have fun tying her up, arms and legs with a harness like this one.
And just go for it, Lick and finger and fuck her till she learns it’s okay and good to cum multiple times. That’s how I was taught 😉