Muchi Muchi Kyousei Seichouchuu!!!

Both are made by the same studio and as such the animation, character design, artstyle, between others is very similar, even the format is very similar (ONAs with two episodes with a short time per episode), Yareruko! Densha Ecchi has some of rapey vibes (not totally, the girls are completely submissive), and Muchi Muchi involves tricking inocent girl who don't know what sex is, so they are kinda alike in that aspect. 

Both Baka Imouto and Muchi Muchi have the protagonist taking advantage of the the female cast, in Baka na Imouto is her sister which is dumb as an ox and Muchi Muchi is various toddlers who got transformed to their adults self (which happens to be stacked), but with the same intelligence, it's basically the kink of taking advantage of a cute innocent person (close to lolicon, but no cigar), the type of body of the girls is similar, lewd, busty and with a cute face, very moe, and the protagonist is also very similar in regards to the looks and actions.