Joy is the Devotional Sex word for intercourse
Joy, for intercourse, is just one of the new words used on this site for talking about sex.The other new words are presented in Chapter 1 here.
Chapter 1 also includes the reasons I have not used the traditional words on this site (see here), as well as the reason I chose the word Joy (see here).
This site also uses new names for the common positions for Joy, and these are presented here.
The Vanilla Sex view of intercourse is discussed in Chapter 2 here.
Devotional Sex takes a more Tantric view, and Joy within Devotional Sex is discussed in Chapter 4 here.