Top 成人网 Secrets
.. The common, unquestioned equation of penile–vaginal intercourse with sexual intercourse reflects a failure to look at systematically 'whether or not the respondent's understanding of the dilemma matches what the researcher experienced in your mind.' Nancy W. Denney; David Quadagno. Human Sexuality. Mosby-Yr Guide. 2008: 273. ISBN 0801663741.