I was able to do it as alpha/stockholmed, but it did take some time. Check in your settings that you have the chances set as high as possible without losing achievements (assuming you care), then be in the wolf lair and strip off most everything, and sleep for one hour repeatedly. Each time (appears to) role a chance that the black wolf will be distressed, at which time you can comfort them, take them in hand, then immediately let go. That usually gives you a one turn window to pick mount/be mounted if you are deviant enough.
If the rng doesn't work out after a full day, you can also reload, then reset it for a fresh set of roles by exiting then re-entering the cave or washing in the stream (something that spends time usually does the trick). Rinse and repeat until you get lucky, then save there and try a similar strategy in the scene to re-roll the pregnancy check.
If you try to keep your arousal around 3/4 of the way full, that should let you time things out nicely.