First of all, wear a small vest with a tube top. Small vests with tube tops are generally simple in style. Just put on your underwear and put the tube top on the outside. This can not only cover the underwear, but also prevent the bare chest.
If the neckline of the straight collar is too big, it can be slightly smaller to make the collar less exposed, which can also reduce the risk of exposure.
You can add a small sling on the basis of the straight collar, of course, it is best to use the same color as the clothes to make the sling more exquisite, which will not destroy the aesthetic feeling of the clothes, but also prevent light leakage.
Then, when bending over or doing big movements, pay attention to cover the chest to avoid the neckline slipping and the chest being exposed.