Forum:Lava golemn

me and my friend were dueling, i had one monster on my side of the field, he had one, too, it was my turn, i drew a card, then summnoned a monster on my side of the field, then, he said he special summoned lava golem with my two monsters, because as the card says, sacrifice two of your opponents monster to special summon this on your opponent side of the field. can my opponent special summon lava golemn on my side of the field with my two monsters, right after i had just placed a monster on the field?