Personally, I am used to washing my underwear and socks separately. However, if you are used to putting the two together, it is okay, but I recommend you do the following to ensure personal health and hygiene.
Items You Should Be Washing Separately From the Rest of Your Laundry
Is it gross/unsanitary to combine kitchen towels with sock & underwear in the washer? - Page 2 - General Education Discussion Board - The Well-Trained Mind Community
再也不能忍受每晚手洗内裤了,有没有解决办法? - 匿名用户的回答- 知乎
再也不能忍受每晚手洗内裤了,有没有解决办法? - 知乎
Do you wash your underwear with your other clothes? - Quora
再也不能忍受每晚手洗内裤了,有没有解决办法? - 知乎
Items You Should Be Washing Separately From the Rest of Your Laundry
我跟老妈有分歧:内裤和袜子到底能不能一起洗?
再也不能忍受每晚手洗内裤了,有没有解决办法? - 知乎
再也不能忍受每晚手洗内裤了,有没有解决办法? - 知乎
Can underwear be washed together with socks in the washing machine? - Quora