Terra sigillata is an archaeological term that refers to a specific type of both plain and decorated tableware made in Italy and in Gaul (France and the Rhineland) during the Roman Empire. These vessels have glossy surface slips ranging from a soft lustre to a brilliant glaze-like shine, in a characteristic colour range from pale orange to bright red; they were produced in standard shapes and sizes and were manufactured on an industrial scale and widely exported. Usually roughly translated as 'sealed earth', the meaning of 'terra sigillata' is 'clay bearing little images' (Latin sigilla),. The archaeological term is applied, however, to plain-surfaced pots as well as those decorated with figures in relief.
Terra Sigillata industries grew up in areas where there were existing traditions of pottery manufacture and where the clay deposits proved suitable, while their distribution casts light on aspects of the ancient Roman economy. The six reliefs depict couples engaged in an array of amorous positions. The purpose of such scenes was to mainly titillate the users of the lagynos. References:
Catherine Jones, Sex or Symbol. Erotic Images of Greece and Rome (Austin 1982), pages 125-130, for a discussion of vessels of this type and their decoration and meaning.