Since someone mentioned PN3, we can't go on here without mentioning its younger cousin, Haydee:

But Haydee is probably the opposite of mainstream gaming, so it probably doesn't qualify for this thread. Can't really think of anything mainstream at the moment...maybe the sex scenes in Wolfenstein: The New Order? The fanservice in Final Fantasy XIV? Getting into some non-consensual action with a muscular russian woman in Alpha Protocol? Pyramid Head raping some mannequins in front of James on Silent Hill 2? Yea, lemme just stop here...

Also OP, can't post sexy Raiden (I totally agree with your choice, good lad) without this extra add to that whole sequence:

https://www.youtube.com/watch?v=QgEOBCTeVtE