Since you can't tame them it seems hard to get titanoboa eggs. However, you just have to build a small pen with open roof, get your argent/quetzal and drop some titanoboas in there. Since they won't despawn, you have an infinite source of kibble!!
You can pick these up with an argy, and fly to an enemy or an enemy base and drop it in there. The tribe log will only say a wild titanaboa killed their Dinos. This doesn’t work if they aren’t on passive