You could find no other part (to slap) but the prominent part of her face. See I was one of the seven sons of Muqarrin, and we had but only one slave-girl. The youngest of us slapped her, and Messenger of Allah ﷺ commanded us to set her free. 2097
لَهُ سُوَيْدُ بْنُ مُقَرِّنٍ عَجَزَ عَلَيْكَ إِلاَّ حُرُّ وَجْهِهَا لَقَدْ رَأَيْتُنِي سَابِعَ سَبْعَةٍ مِنْ بَنِي مُقَرِّنٍ مَا لَنَا خَادِمٌ إِلاَّ وَاحِدَةٌ لَطَمَهَا أَصْغَرُنَا فَأَمَرَنَا رَسُولُ اللَّهِ ﷺ أَنْ نُعْتِقَهَا