John 13 - Rabbi Jesus strips naked & uses his loin cloth to wash the "feet" of his teenage disciples (Jesus referred to them as his "little ones" who were too young to pay the Temple tax). Feet (regel) was ancient Greek/Hebrew euphemism for genitals, while uncovering & washing of "feet" was a common idiom for exposing the genitalia often in a sexual context.

Jesus then instructed his disciples to do for each other as he had done for them, the followers of Christ, now impregnated with God’s Holy Spirit & instructed to be as "one flesh" connected to each other even closer than siblings, so that the world will see that ours is the true God of the world. This message is reiterated later in John’s gospel with Jesus explicitly stating “I pray that they will all be one, just as you and I are one–as you are in me, Father, and I am in you. And may they be in us so that the world will believe you sent me.” Jn 17 : 21 NLT

After the foot washing, "the one Jesus loved", John reclines close to Jesus, his head resting on Jesus's breast.

This has been interpreted by modern Christians with modern cultural bias, as Rabbi Jesus acting as an example of humble servanthood. However, early Christians-JEWS likely understood Jesus serving his disciples, very differently.