High cut denim shorts, sleeveless lumberjack vest, USA muscle bandanna that has the US flag for it's design, Valeo belt*, Knee high Otomix boots or Colorado shoes, a 3 gallon water bottle in one hand and a cooler in the other containing your brown rice and plain baked chicken breasts will let you stay anabolic while also letting others know discreetly that you're into lifting.
If the party is indoors and / or in the evening, you may also want to wear Ray Ban sunglasses to complete the look.
* optional