Oh, Chekov was clearly planning on raping her. At least as clearly as NBC Broadcast Standards would allow them to intimate in 1968.
If anyone would try to rape a woman like that, he'd end up with his balls up his throat. For a klingon woman she wasn't putting up much of a fight or for any woman for that matter.
Once again, 1968. Women were still seen as delicate flowers much of the time. Even Klingon women.
The intent of the scene is very clear. As it was in "The Enemy Within" and "Gamesters of Triskelion".
People confuse the primary colors and theatrical acting as camp when, in fact,
Star Trek was rather dark thematically much of the time. The Red Hour from "Return of the Archons" comes to mind as well.