In drug culture, the phrase "got your legs" or "getting your legs" is not a commonly known or widely used term with a specific meaning. Drug slang and terminology can vary among different regions and social circles, so it's possible that this phrase has emerged in a specific context or location that I am not aware of
However, if you suspect that your best mate has "graduated from blow to something grave," it's essential to take your concerns seriously and address the situation. "Blow" is a common street name for cocaine, and if your friend is moving on to more dangerous substances, it could indicate a worrisome escalation in drug use.
In such a situation, it's crucial to approach your friend with care and compassion. Try to have an open and honest conversation about your concerns and feelings. Express your worries about their well-being and the potential risks associated with drug use. Encourage them to seek professional help and support if needed.
If you feel that your friend's drug use is putting them in immediate danger or causing severe harm, consider reaching out to a trusted adult, counselor, or a helpline specializing in substance abuse for guidance on how to handle the situation and provide support to your friend.
Remember that drug abuse and addiction can be complex issues, and your friend may need professional help and support to overcome these challenges. Encourage them to seek help, but also take care of yourself and consider seeking support from others who can assist you in supporting your friend through this difficult time.