If you want Lona to have sex with a specific race, like goblin/orkind for example, there is a simple way to do it without having to be brutally beaten. Here is what I do: First you meet them in an encounter. Even the three goblins in the sewer at the beginning are good to use, if you are careful. The best way to get a good group though, is when you rest in the wilderness to always rest near the exit. Like two spots away. You're very safe here, but save beforehand just in case. Higher world difficulty means higher chances of monster groups spawning. If you rest and skeletons appear, then just reload. Some if a boar is goring you when you wake. If it's goblins, then chances are high for sex! You'll need high stamina (which you SHOULD have since you only just woke up from resting), and you can't be playing on Hardcore or this probably won't work (since you can't leave an area while in combat, in hardcore.. it's possible, but still...).
Since you're near the edge of the map you won't be near many goblins, if any. If you got goblins and nobody sees you yet, then save on Slot A. Now strip Lona completely or she will get hit, and then it's easy to lure a single goblin/orkind near you. Go to your menu and hotkey the "surrender" skill. I usually use the R key. Save now on Slot B. Get near the goblin and press the corresponding key. This will make Lona lay down with stars over her head. The goblin might fuss about a bit, but it will eventually grab Lona (sometimes they will just jack off and squirt on Lona a few times first). You'll soon see which type of sex the goblin is about to engage in. If you want straight up vanilla sex then you want to see the thing's penis in her vagina. Anything else and you're probably going to want to hold alt, tab, and click the x button to close. Start up again and reload. Try try again. Even vaginal sex is no guarantee though. Sometimes the goblin will pull out, but it's mostly the humans that do this (I don't know why...?). If you're lucky then Lona will get an epic cream pie and her cooter will be at 25% to 75% capacity. You could just leave after this, if you only want pregnancy as the result. If you want to keep having vaginal sex then save again on Slot B and repeat as much as you like. You can even have Lona crawling but don't allow her stamina to reach -100. Generally it's a good idea to crawl to the exit at -50 stamina or less. You can then re-enter the area, now with no enemies, feed Lona to 90+ hunger, save, and try to sleep. Sometimes you'll get an enemy encounter but Lona should have enough stamina to escape. If you rested in a swamp then RIP. xP
Now, if you wanted to just get Lona pregnant and got her a nice cooter cream pie, then all you have to do is not clean her privates. That mess will slosh around in there well long enough to get Lona preggers. If you DON'T want Lona to get pregnant then I suggest cleaning it out ASAP, as well as bathing after that. I think this would get most of it, but there's no guarantee...
If you want to build up Lona's vaginal skill then just masturbate. It's just easier and less risky. You could then try out the high skill on prostitution later or whatever.
Also giving birth results in an average cooter and will drastically lower Lona's vaginal skill, but it will tighten back up over time, even becoming tight and then micro again.
You can also use these methods to have only anal sex if desired. In my game Lona doesn't bleed vaginally anymore. Not sure if anal sex ever stops bleeding though...?
Oh, another tip for luring enemies: You can lure them from further away if you hold the shift key. Even without actually moving. I use it a lot when luring two boars into ramming each other...