↑Sexual intercoorse maist commonly means penile-vaginal penetration for sexual pleisur and/or sexual reproduction; dictionar soorces state that it especially means this, an scholarly soorces ower the years agree. See, for example;
Richard M. Lerner, Laurence Steinberg (2004). Handbook of Adolescent Psychology. John Wiley & Sons. pp. 193–196. ISBN0471690449. Retrieved Aprile 29, 2013. When researchers use the term sex, they nearly always mean sexual intercourse – more specifically, penile-vaginal intercourse... The widespread, unquestioned equation of penile-vaginal intercourse with sex reflects a failure to examine systematically 'whether the respondent's understanding of the question matches what the researcher had in mind.'
Fedwa Malti-Douglas (2007). Encyclopedia of Sex and Gender: A-C. Macmillan Reference. p. 308. ISBN0028659619. Sexual intercourse. [T]he term coitus indicates a specific act of sexual intercourse that also is known as coition or copulation. This 'coming together' is generally understood in heteronormative terms as the penetration of a woman's vagina by a man's penis.
Irving B. Weiner, W. Edward Craighead (2010). The Corsini Encyclopedia of Psychology. 4. John Wiley & Sons. p. 1577. ISBN0470170239. Retrieved August 21, 2013. Human sexual intercourse, or coitus, is one of the most common sexual outlets among adults. Sexual intercourse generally refers to penile penetration of the vagina...CS1 maint: Uises authors parameter (link)
Clint E. Bruess, Elizabeth Schroeder (2013). Sexuality Education Theory and Practice. Jones & Bartlett Publishers. p. 152. ISBN1449649289. Retrieved December 5, 2014. Vaginal sex is defined as when a penis or sex toy is inserted into a vagina for pleasure. In many cultures around the world, vaginal sex is what is usually implied when people refer to 'having sex' or 'sexual intercourse.' It is the most frequently studied behavior and is often the focus of sexuality education programming for youth.CS1 maint: Uises authors parameter (link)