There are no direct answers to it. Vulgarity and obscenity are quite loosely associated to anything sexual but this ad is slightly different. It is sexy, naughty (both positive words used by me) and still in a bad taste.
The new bride comes to 'ghat' for washing clothes where she is being critically examined by elderly neighbourhood women but she takes out the Amul macho male underwear and once she starts washing it, the 'creative' ad-makers take this ad to another level of 'indecency'.
She makes suggestive movements. The camera actions suggest that she is doing something really naughty!
Then the camera moves again. She picks up the bat (used to hit the clothes) to do the laundry as if she is about to do a really nasty thing (more so, because it is in public). The naughty grin on her face marks the end of the ad.
The tagline of the ad is 'Crafted for Fantasies' and it appears the woman is living her fantasy in front of everybody. Daring but uncomfortable for persons watching it amid family. At Exchange4Media, a reviewer writes:
The girl, gauging their intentions, decides to be brazen and boldly brings out her husband’s underwear from the lot. The women are taken aback by its sheer size and they retreat to a corner. She further continues to make suggestive movements while washing the underwear, knowing that the women are watching her, and absolutely enjoying the act and the onlookers’ discomfort.Another reviewer says:
The girl gets turned on by just looking at the big sized male underwear and fantasizes about the 'act', inviting resentful glances of the women around. Ye to bada toing (toying...?) hai, Crafted for fantasies, is the catchline.
(In photo above, the woman with the bat/hammer in her hand, readying for action)