Amberson J I, Hoon P W
Arch Sex Behav. 1985 Aug;14(4):351-60. doi: 10.1007/BF01550850.
Seventeen women masturbated to orgasm several times in succession while being measured intravaginally by a device that allows continuous oxygen and blood flow readings. Analysis of covariance showed significant differences between fantasy and orgasm and between orgasm and interorgasm relaxation periods. The data do not provide physiological evidence that successive orgasms are either physiologically or subjectively stronger but do provide physiological evidence of a plateau phase of sexual response in women.