Roleplay ideas, or offer your own or variants of these:

 

Eowyn found herself defending the caverns and peasants beneath Helm's Deep when she wanted to be out fighting with the men.  Soon she discovered that some uruks had found a secret way in that could cost them the battle...unless she stalled them with the only thing that would keep a group of horny evil uruks busy for hours...  Afterwards, they might take her back to their camp where she could continue to work her mischief.

 

The people of Rohan are known for their bond with horses, but Eowyn takes it too far, often in the dead of night in the stables or when she's alone out in the woods.

 

To get revenge on that bitch Arwen for stealing Aragorn from her, she hires a group of orcs or mercenaries to teach the haughty elf a lesson, letting them practice on her first to make sure they will do it right.

 

Angry at her uncle, the king, she rejects all the brave and noble suitors he sends her way only to rutt and sell her body to the lowest men in Edoras, the more shameful the act the more the disturbed shieldmaiden is likely to agree to it.  Her twisted desires are an open secret in the court and town, but no one dares tell the king for his wrath against them.

 

OOC:

 

I usually don't go for canon males like Aragorn or Theoden, but a sleezy and disgusting Grima might be okay if done well and nastliy enough.  I usually prefer the uruks or more generic men/creatures.