The Alpha male werewolf appears at certain time intervals at night in the forest, or at the wolf den.
There are 2 ways to get Alpha male fluids
1. Max out his libido and get the fluids (cum in this case). This is the easiest way to achieve it.
Or if you want to keep the hero stats high and bitch fame low
2. Battle the Alpha till you beat him and get the fluids (blood in this case). You will need a really buffed out character (high strength and endurance. Alternately agility in place of endurance will help a lot to avoid most hits) and a lot of healt & restrain potions.
Better equipment is also a great help. If you haven't completed the Lizard tribe and gotten the spear and amulet, I recomend doing the tavern quest to deal with the rat problem sothat you can gain access to the underground. There you can mine Diabostite and sell it to the blacksmith Blake. He will then make Diabostite weapons that are better than the rest of the equipment you can ordinarily buy.
If you got the silver knife from Logan, that could also be worth using as werewolves are vulnerable to silver.
It would be better if you can make strong health and/or restraint potions, aswell as silver bombs for the prolonged fight. Regen powder is also advantages to have.
You can also alternate fighting and teasing to control the flow of battle with the Alpha, just be careful as he gets help from 2 of the brown/blue werewolves at a time during your fight.
Hope this helps~