Wrote a review on this, here it is:
https://terrenceswiff.wordpress.com/2016/03/09/youkai-shoujo-monsuga/
This series has my favor. I think you could argue for it being the best among lewd battle harem manga. Of course, I can understand why some might disagree given its unconventional-for-harem ways, but I dig it. Hilarious series, and there's a lot of good content that awaits should you choose to pick it up!