Yeah, but I wouldn't say it's bad game design, it's just a hard problem to solve. Mainly, this form of sex scene is a consequence of the way video games have been designed for a long time. The most common obstacle in a video game is an enemy. Your method of defeating enemies in 99% of games is violence. Guns, fighting, jumping, etc. As long as the game plays like a conventional game, the only context for sex to happen in a "reasonable" manner is when the character loses.
I've seen games where you can initiate sex with defeated opponents, this does work a bit, rewarding good gameplay. But it does bring up an issue sex on loss brings up. They're rape. Unless you have some way to frame it, either scenario is forced sex, so it is inherently uncomfortable to most, downright a turn off for some.
Sex scenes can also be used as a reward for significant success. Like if you clear a level, complete an arc, etc. But then the sex scenes feel detached from the gameplay. The best way to make sex feel natural and part of the game is to deviate from traditional game genres, develop in genres outside of the popular ones.
I find myself playing VNs and Management Sim games more, they don't have nearly as hard of a time trying to bridge the gap of gameplay and sex (they are also much easier to play one handed).