According to Kenyatta

Hapo kitambo among the things taught during this period before marriage, were “matters relating to rules and regulations governing sexual indulgence.”
The youth of that time @Electronics4u went through training of the control of sexual energy by a method referred to as Nguīko a method of intimate contact between a woman and a man that did not involve penetration.

After the healing process of the circumcision, young men returned and grouped themselves into several young men’s huts, thingiras, where the initiation ceremonies in the form of teaching were held. It is here where circumcised girls of the older initiation set came and performed Nguīko with the men initiates. This Nguīko could happen at first under the supervision of the matrons in charge of the girls’ training but they were soon left alone after they internalized the rules. It would then continue with different partners until marriage which ended the group sharing but would continue within marriage.

song to foreskin party :
Tugithii rui, tugithii rui, ii wari ndunyu; Thigiriri yaiganaga mbogo ii wari ndunyu

Teach them bana.