If you decide to breed Magmasaurs, be careful if you build a gate around the area to keep stuff away, if it blocks the magma flow, your Dino will read “needs lava to mate” even while standing inside the lava. Just remove the gates blocking the lava until that notice goes away.
If you keep the male breeder in your hot bar, you won’t get them all confused while lining them up in the lava.
My dad came up with a fool proof strat, using a high level procoptodon, you can circle around the lava and aggro every magmasaur, but you are much faster, so do a circle and while they’re on the other side, hop off and grab the eggs, get back on and hop around, before you know it, you have every egg in cave
I’ve found the eggs. The eggs are located inside the volcano in an amethyst cave. There are lava pools with groups of magmasaurs in them. There are small islands with craters in them, within those craters the eggs are nestled within. But be careful there are lots of magmasaurs, magma, and what look like varient rock elementals.
Easiest thing to do is to spawn at the East zone and go to the Egg-Straction mission. Then, take the first left in the cave and you should end up by the nest. A good strategy is to wait until there aren’t any magmasaurs by an egg, then ask HLNA to teleport away, and right before you teleport, grab the egg.
Get yourself a good dinosaur with a hefty amount of attack, that can kill them fast. if you ever want a chance to get one of their eggs you need to be able to kill them fast, because they can shoot a shot of magma that can kill you even while mounted. Be extra careful running through the volcano! If it starts to erupt, teleport the hell out of there. You will instantly die when it does.
If you can transfer your Rock Drake to Genesis it is pretty easy to steal Magmasaur eggs with them. Just turn invisible look for the best egg to steal. Quickly dismount grab the egg get back on and haul your butt out of there.