セックスの科学

Like any sexual position, the missionary should be preceded by foreplay,

an essential part of intercourse which makes penetration easier.

For the vagina to lubricate and for the vagina to elongate and to balloon at the end to allow...

Foreplay can involve just normal kissing, it can involve touching, vagina and the penis, or even oral sex.

The stimulation of stroking and sucking makes the breast grow in size and the nipples harden.