Omg i love so much this kind of thing when there are a stalker ლ(´ڡ`ლ) ε=ε=(ノ�...

Try this!

http://www.mangago.me/read-manga/glen/

Here’s an…interesting one:
http://www.mangago.me/read-manga/kawaii_senpai_no_kaigoroshikata/

This one has multiple stories and the second story has a stalker: http://www.mangago.me/read-manga/taka_ga_fukuen/

Must must check out Color Recipe. It's a masterpiece by harada which puts all other stalker/yandere bl and het stories to shame.

Thank you all for your recomandations !! Σ(っ°Д °;)っ
(≧∀≦)

Unfather has the same vibe but not 100% stalkerish

hikizuru oto (the dragging sound) by harada. it's short and not really stalker, but it's p twisted.