Does one who fondled his companion until semen was discharged, while in a state of Ihram, have to offer expiation and repeat the Umrah?

You have committed a grave error, and you must repent for it and avoid being in seclusion with young people with whom you fear temptation. According to the majority of scholars, a sheep is obligatory upon you, while according to the Hanbalis, a camel is obligatory, this is if you emitted semen.

However, if you circumambulated the Kaaba without performing ghusl after emitting semen, then this circumambulation is invalid according to the majority of scholars. You remain in your state of ihram according to them until you release yourself by performing Umrah, unless you subsequently entered into ihram for another Umrah or Hajj. Other scholars hold that the circumambulation is valid, but it must be compensated for with a blood sacrifice.