Stains such as you describe do not make you
niddah. We believe abstaining from relations is an important precaution, so that you do not find yourself becoming
niddah while having relations. If this were to occur, it would be an inadvertent transgression of a severe Torah prohibition.
This precaution relates to relations alone, and not to other forms of physical contact. Even if you choose to adopt this precaution of avoiding relations for 24 hours, you are not obligated to abstain from other physical contact, nor do you need to keep the
harchakot.