Your first roll is your best. Not necessarily for all the reasons people put up here (tolerance) but because it's your own personal first time experiencing the wonderful (temporary) changes in brain chemistry that feels so absolutely incredible.
I'd say candy flip your second time, seriously, everyone can recall how absolutely awesome their first MDMA experience was. other times can be just as awesome/intense/potent but there's still that little factor of "I don't know what this is going to feel like... HOLY SHIT IM ROLLING BALLS, I get it" that can never be replaced.
So, don't taint the experience! The first time u smoked weed, the first time u took L, the first time u got drunk. It's always fun and different, but MDMA, my friend, that is a whole new ball game.
Try to have a friend take a tally of how many times u proclaim something along the lines of "I just feel so GOOD!"
Oh, and drink some orange juice, it's hella tight