Can Someone Help With Parsing Please?

[indalo]

35D 'Do sex repeatedly with mate in social fashion'

Although I completed this crossword very quickly, I am troubled by my inability to fully parse my answer which is, 'CONVIVIALLY'. The 'CON' and 'ALLY' parts are obvious but 'VIVI'? Other than a repeated reference to the number 6 in Roman numerals, I don't understand any connection with sex.....unless I have led a really sheltered life. Is it perhaps a dialect thing - six (sex)?

[Mamyalynne]

Yes, scroll down to 'origins'

http://www.dictionary.com/browse/six

[Lie-in King]

Convivially - 'con' (do) + 'VI' (sex; Latin "six", x2) + 'ally'

[Togo]

VI=6 Roman Numerals. VIVI repeatedly

[Mamyalynne]

I didn't mean yes to 'dialect' rather - six = sex

[indalo]

Thank to those who responded, particularly 'Mamyalynne' for providing the reference showing the linguistic origins.