Digital flavour modulation represents a significant research challenge within Human-Food Interaction. Previous work has focused on modulating basic tastes, while the modulation of trigeminal sensations such as spiciness and coolness remains underexplored. Spicy and cool substances contribute substantially to the sensory appeal of food and beverages; however, their overconsumption can have adverse health effects. To enhance these trigeminal flavours without chemical additives, this study proposes an integrated multimodal approach combining electrical tongue stimulation with congruent olfactory stimuli. Unlike unimodal methods, our approach leverages the interaction between direct neural stimulation and olfactory integration to selectively modulate distinct spiciness and coolness perception. Psychophysical experiments demonstrated that our method significantly enhanced perceived coolness through combination of electrical tongue stimulation and lemon odor, and significantly enhanced perceived spiciness of a spicy solution by electrical tongue stimulation. These findings suggest that our method expands design space for digital flavour modulation and contributes to healthier and more enriched eating and drinking experiences.