The attack selection isn't quite random as there are calculations involved. While she doesn't attack based on your previous attack at all, she tries to forecast what attack to use based primarily on the target's health+shield ratio vs the target's lust ratio, so whichever ratio is closer to the target's defeat, she'll go for that respective attack. That is, if the target's HP+Shield is closer to 0%, she'll attack HP, but if the target's Lust is closer to 100%, she'll use a lust attack. If the target is immune to lust, she'll target health+shield only.
Though with this, for the next release, I've added an extra toggle in the drone targeting menu for any item that is classified to have dual attack types (at current, it's only Siegwulfe). So the toggle cycles between HP, Lust, and Automatic (default), and selecting a new target will also reset the toggle. So now you are able to choose which attacks you want her to use, though be mindful that after a select target has been defeated in a group combat, you may want to change the attack toggle for the new target before taking your turn, just to make sure you're using the attack you want.
I also found some other minor bugs and oddities with Siegwulfe content that I also addressed for the next release. After dropping or selling the Siegwulfe item, her follower flag should properly reset so you will be able to purchase her again (after a 24-hour cooldown)--this might not be an issue now, but there was potential that she could be lost in the void if the flag wasn't reset at that point. Re-buying her would also reset her genitals, so she will no longer be considered a Dom, for those who want to revert her to her previous state (though again, this is probably how it already works).
As for the eggnancy when she is a Dom, this was intentional as a permanent feature for the Dom variant of the Siegwulfe (meaning there wasn't supposed to be a switch for it), so I don't think I'll make a toggle for it unless all the areas that mention it have written variants to accommodate, as well as some scenes needed to make it happen. Basically there needs to be a rationale behind it being toggleable.