In a small saucepan, combine the sugar and water and bring to a simmer over moderately high heat, stirring to dissolve the sugar. Remove from the heat and let cool to room temperature. Stir in the lemon juice.
In a large pitcher, combine the lemon syrup with the guava nectar, tea and tequila. Pour the teaquila into tall glasses over ice and garnish each with a lemon twist.
The teaquila can be refrigerated overnight.
Guava nectar is available at supermarkets and health food stores.